Mrebo said:

I would however point out that Anakin was from Tatooine. That Yoda wears hermit clothes while living as a hermit doesn't inform very much. And what of Luke wearing all black in ROTJ while asserting his Jedi-hood? If it were so established, wouldn't they have stuck him in "Jedi robes"?

LUKE

But I need your help. I've come back to complete the training.

YODA

No more training do you require. Already know you that which you need.

Yoda sighs, and lies back on his bed.

LUKE

Then I am a Jedi?

YODA (shakes his head)

Ohhh. Not yet. One thing remains: Vader. You must confront Vader. Then, only then, a Jedi will you be. And confront him you will.

He's not a Jedi until the end of the film.