Honestly, the only way I can think of to reasonably play a psi crystal is as a warlock with obtain familiar. The familiar can carry you around and be your eyes and ears, and since it has an intelligence score, it can do that on its own without the hassle of trying to control an animal with literally no way to communicate with one (since telepathy can only be used with creatures that have language). And warlock because it doesn't care about the stats and is the only arcane class that doesn't need hands to manipulate components.

Wait, nevermind. Invocations still have somatic components. So, that just leaves wisdom/charisma based psionics, but they can't get familiars. I guess you'll have to use some of your starting gold to hire a commoner to carry you until you reach a high enough level to start dominating them, instead? At that point, I'd probably rather just play a human commoner with a pet rock they think can talk to them.