The good news is that it's not overpowered. Short recharge use of the Violent Thrust option for Telekinesis is probably the cheapest thing you can do with your spell, and that's not excessive for an eighth level spell. It might even be a bit underpowered.

The bad news is that Mental Pinnacle already exists. "Psionic" already has a very specific meaning in D&D. If the DM likes them, he'll probably want to go with the system as it exists, power points and augmentations and all. If the DM doesn't, asking for the ability to let your magic unlock mind powers will probably get turned down on the basis of flavor alone.