The personality type Nine corresponds to Jung's introverted sensation type.
(Si dom) Jung describes what we would regard as average to unhealthy Nines, people who maintain their peacefulness and connection with others not as they are, but through an idealization of them. The other person may feel "devalued," as Jung says, for the following reasons:
...he may be conspicuous for his calmness and passivity, or for his rational self-control [especially, for example, if the Nine has a One-wing]. This peculiarity, which often leads a superficial judgment astray, is really due to his unrelatedness to objects. Normally the object is not consciously devalued in the least, but its stimulus is removed from it and immediately replaced by a subjective reaction no longer related to the reality of the object. This naturally has the same effect as devaluation. Such a type can easily make one question why one should exist at all...
Seen from the outside, it looks as though the effect of the object did not penetrate into the subject at all. This impression is correct inasmuch as a subjective content does, in fact, intervene from the unconscious and intercept the effect of the object. The intervention may be so abrupt that the individual appears to be shielding himself directly from all objective influences... If the object is a person, he feels completely devalued, while the subject has an illusory conception of reality, which in pathological cases goes so far that he is no longer able to distinguish between the real object and the subjective perception... Such action has an illusory character unrelated to objective reality and is extremely disconcerting. It instantly reveals the reality-alienating subjectivity of this type. But when the influence of the object does not break through completely, it is met with well-intentioned neutrality, disclosing little sympathy yet constantly striving to soothe and adjust. The too low is raised a little, the too high is lowered, enthusiasm is damped down, extravagance restrained, and anything out of the ordinary reduced to the right formula—all this in order to keep the influence of the object within the necessary bounds. In this way the type becomes a menace to his environment because his total innocuousness is not altogether above suspicion. In that case he easily becomes a victim of the aggressiveness and domineeringness of others. Such men allow themselves to be abused and then take their revenge on the most unsuitable occasions with redoubled obtuseness and stubbornness. (C. G. Jung, Psychological Types, 396-397.)