I'm just wondering what emulator is allowed, a run for Rue Any% NG+ says it used an emulator but not what one

I would say that anything allowed by tasvideos.org is good enough for me. http://tasvideos.org/EmulatorResources.html

That said, I wouldn't reject a run based on emulator used unless I had reason to believe it was specifically inaccurate.

Out of curiosity - what about PSP, PS Vita, or PS TV? I know from my casual experience with the game that it runs decently on the PS TV. That said, I don't know how frame rates or other stats would compare for an actual runner.