Nice to know someone's interested! Once I saw your response, I begun to check the Kai forums. Turns out some people got Kai to work with the Vita; take a guess on which game they tested the connection.
From what I read, their results seem similar to me and what I've got going with a PSP 2000. All I know is that my adapter recognizes the ad-hoc signal, and kai recognizes the adapter. No clue if I'll be able to play with others; it might be a bit weird to jump into a room just to see if I connect, but there aren't many people to begin with, let alone rooms.