As I have said in the title, it is actually now possible to TAS PS Vita games, with Vita3K, and libTAS, however, this is very buggy and needs to be worked on, cause sometimes, the emulator will crash in random spots, however, this can be fixed soon with new releases of Vita3K, and libTAS. The emulator is very experimental, and is still in a very early alpha stage, most games do not work, but some do, the only games I have tested are, both the Sonic 1 and Sonic 2 Decompilation ports for the PS Vita, I expect a lot of other games will be able to be TASed in the following future. [This was just quick and major news for TASVideos].
If you want to download the emulator, here is the link: vita3k.org
Vita3K setup tutorial (NOT MADE BY ME.):
https://www.youtube.com/watch?v=p9C3-imZFpo
PS Vita Retail Game Checklist:
https://vita3k.org/compatibility.html?lang=en
PS Vita Homebrew Checklist:
https://vita3k.org/compatibility-homebrew.html?lang=en