Okay, most of that bounced right off. Let's try from another direction: let's look at the Freudian model of the psyche and make predictions about what we'd expect, then compare it to the mappings to enneagram types.
The Id
So, first up is the id. Let's start from wikipedia:
The id (German: Es) is the unorganized part of the personality structure that contains a human's basic, instinctual drives. Id is the only component of personality that is present from birth. It is the source of our bodily needs, wants, desires, and impulses, particularly our sexual and aggressive drives. The id contains the libido, which is the primary source of instinctual force that is unresponsive to the demands of reality. The id acts according to the "pleasure principle"—the psychic force that motivates the tendency to seek immediate gratification of any impulse—defined as, seeking to avoid pain or unpleasure (not 'displeasure') aroused by increases in instinctual tension. If the mind was solely guided by the id, individuals would find it difficult to wait patiently at a restaurant, while feeling hungry, and would most likely grab food from neighbouring tables
Okay, so let's make some predictions about someone dominated by the id:
Energy Level: high (nothing restricting the flow of energy from the id)
Adaptation to reality: low
Ability to balance competing demands: low
Okay, now let's do a check on the enneagram id types (3, 7, 8).
Id Enneagram types
Energy level: high; good fit
Adaptation to reality: low; good fit for 7 & 8. Not a great fit for a 3s. 3s tend to be all too adaptive to their external reality, and cut off from what they really want and need.
Ability to balance competing demands: low; a reasonably good fit.
Okay... that wasn't perfect, but not bad. Next up, the ego.
The Ego
The ego (German: Ich)[18] acts according to the reality principle; i.e. it seeks to please the id's drive in realistic ways that will benefit in the long term rather than bring grief. At the same time, Freud concedes that as the ego "attempts to mediate between id and reality, it is often obliged to cloak the Ucs. [Unconscious] commands of the id with its own Pcs. [ Preconscious ] rationalizations, to conceal the id's conflicts with reality, to profess ... to be taking notice of reality even when the id has remained rigid and unyielding." The reality principle that operates the ego is a regulating mechanism that enables the individual to delay gratifying immediate needs and function effectively in the real world. An example would be to resist the urge to grab other people's belongings and buy them instead.
[...]
"it serves three severe masters ... the external world, the super-ego and the id."[20] Its task is to find a balance between primitive drives and reality while satisfying the id and super-ego. Its main concern is with the individual's safety and allows some of the id's desires to be expressed, but only when consequences of these actions are marginal. "Thus the ego, driven by the id, confined by the super-ego, repulsed by reality, struggles ... [in] bringing about harmony among the forces and influences working in and upon it,"
Umm... huh. Seems like in the Freudian system, having a dominate ego = health and balance. That either doesn't really fit any enneagram type (at unhealthy levels) or fits every enneagram type (at high health levels). Plus, the ego has to deal with three masters, one of which isn't represented in our ennegram to Freudian psychic structures mapping at all. And it's the ego that does the coping and deploys defense mechanisms for every type. It's almost like these are two entirely different systems and finding corresponses is fun and intriguing, but not much more.
Oh, well... I'm sure it'll all work out. So, what predictions would we make about the ego types:
Energy Level: medium (manages to meet some of the needs of id, but constrains it as need)
Adaptation to reality: extremely high
Ability to balance competing demands: extremely high
So now let's look at our enneagram ego types (4, 5, 9):
Energy Level: low; not the medium predicted
Adaptation to reality: low to high (rather than high as predicted); 4s and 5s tend to make minimal concessions to outside reality, and 9s tend to over-adapt to the needs of those around them, losing touch with their own needs. None of those sound ego-like at all.
Ability to balance competing demands: low; not the high predicted. Like every ennegram type, balance only comes with health.
Huh... that was a total mess. Healthiness really only resides in the ego in the Freudian model, and our predictions were way off. Well, let's struggle on to the last. The superego:
The Superego
The superego (German: Über-Ich) reflects the internalization of cultural rules, mainly taught by parents applying their guidance and influence. Freud developed his concept of the super-ego from an earlier combination of the ego ideal and the "special psychical agency which performs the task of seeing that narcissistic satisfaction from the ego ideal is ensured ... what we call our 'conscience'." For him "the installation of the super-ego can be described as a successful instance of identification with the parental agency," while as development proceeds "the super-ego also takes on the influence of those who have stepped into the place of parents — educators, teachers, people chosen as ideal models."
Hmm... so in healthier people (whose development proceeds) the superego's demands are somewhat malleable, but it isn't itself governed by the reality principle (that's the ego).
So, we'd predict someone dominated by the super ego to show:
Energy Level: very low (since the superego stymies the id's energy flow at every turn)
Adaptation to reality: low (for the unhealthy) to medium low (at higher health levels)
Ability to balance competing demands: low, since the superego doesn't care about reality or the id.
Now let's look at our superego types: (1, 2, 6)
Energy level: medium to medium high; not as predicted. 1, 2 & 6s all are generally "doers" who generally don't struggle with low energy as a primary issue.
Adaptation to reality: low (1s, if you squint) to medium (2, 6). 6s tend to look to external sources for certainty (or attack them, when couter-phobic). 1s can be overly rigid, so we could count that as a "low."
Ability to balance competing demands: umm... 1s tend to be overly rigid, 2s tend to try to meet the needs of those around them at the expense of other things, 6s tend to fall in line with or against authority. So... low, or varies according to health level.
So... that turned out to be a big muddle. Energy levels don't really work out. Adaption to reality really doesn't work out. In the Freudian system the only way out is for the ego to be in charge, and defense mechanisms are (often unhealthy) ways the ego copes with the competing demands. The enneagram is all about unhealthy defense mechanisms, all of which try to meet the conflicting demands between id, superego, and external reality in different ways. Some of them do, in fact, cede too much authority to the superego, id or to aspects of external reality. But rigidly mapping enneagram type to Freudian psychics structures (especially the ego) does a disservice both the Enneagram and the Freudian psychic model.