I find this to be a good interpretation of Anakin's going over to the dark side to become Vader:
tl; dw version - He saw the hypocrisy of the Jedi Code and that was the deep underlying reason for his change of heart. He changes sides when Mace Windu tries to kill Palpatine.
I would say that for the most part, he's a counterphobic 6. That gives him a very INFJ feel, to me. ISFP also makes sense and explains his penchant for spectacular heroics, but I don't think that fits Vader's persona.
The Clone Wars series depicts him as a very Te-dom Enneagram 8 kind of character: ENTJ even. He's reckless and daring, but there's always a method to his madness and his strategies usually work in a manic Napoleonic way.
The Clones Wars is official canon by the way, so that while the Extended Universe doesn't apply, Clone Wars does.
So, how to synthesize this?
The main thing that suggests INFJ/ISFP-ish to me is his rank emotionality. Te doms aren't like that, complaining that everything is unfair, etc., as they usually bull through whatever is in their way.
But what about an ENTJ under stress. I dunno who here has known any young ENTJs, but I have, and as kids and young adults, they tend to often be remarkably whiny and always getting into trouble, because they try doing things before considering consequences. With inferior Fi, when their plans are foiled, they're as apt to whine about being unfairly punished as they are to Ni-intuit what they did wrong and not make that mistake again.
So perhaps this kind of arc. He starts off as a whiny kid, but he's adventurous enough to build a pod racer and race it on occasion, getting into enough trouble to maybe even get killed. He gets inducted into the Jedi and has a lot of that whining disciplined out of him. He is still often very rash, but it is always in the name of getting something done and fixing things right away, without considering consequences. That's a Te kind of rashness.