It showed the scene when Wanda first came into contact with the Mind Stone/Gem, but it didn't reveal her as a Mutant.
Of course wasn't expecting for it to be reveal in this episode anyway. I mean the Mutant reveal is something expected for the finale.
Some of the flashbacks were her past as a kid in that country from AOU, her meeting the SWORD director to get Vision's body back, but he wouldn't let her have Vision, and her going to Westview that revealed her, and Vision was gonna live there, and grow old together but before the flashback was over after Wanda got upset her powers unleashed the Hex over the town, she created a new Vision, and pretty much created her fantasy world.
It also revealed after she did, the multitude of her spells cause Agatha to come to Westview, cause chaos to Wanda's sitcom world to get her to come out of it, and get Wanda to reveal her true self.
Agatha also revealed she's the one responsible for Peters Quicksilver, but her explanation was kinda confusing. As Han would say it's a bunch of mambo jumbo.
Oh, Agatha is from Salem Massachusetts 1693. The other witches tried to kill her because she typed into powers she shouldn't have, but they failed, and she absorbed their powers, left them as little more than husks including her own Mother.
Seems the episode ended with Wanda in the street who saw Agatha who had the Twins by their throats, and she told Wanda she knows what she is, she has no idea how dangerous she is. She's supposed to be a myth, a being capable of spontaneous creation this is Chaos Magic, and that makes her the Scarlet Witch.
Credit scene was the reveal that SWORD made the White Vision from the comics.
Now while the Chaos Magic reveal could be seen as a debunk to Mutant Wanda there's still the finale, and it could be possible Wanda's Chaos Magic is her Mutant power.
It's also possible the power Agatha typed into could be Mutant power. I mean she absorb the other witches powers? Kinda sounds like Mutant powers to me.
Also can't forget that Disney changed it where Wanda, and Pietro was chosen by Hydra because they had the correct genetic markers for the experiment, and Disney did that after they got the rights to the X-Men.