Characters from this kind of hyper-modern setting are definitely allowed! It is understandable that an AU with lower technology standard would require a few changes from their canon self and we will be lenient towards that. As long as the character does not end up unrecognizable, all you need to do is state on your app which parts of their personality are going to be different.

Maybe you could incorporate circumstances into their AU that would make them more tech-savvy than average joe in the 90s (e.g. involvement with research or a computer company), but in the end the AU backstory is all up to the player and whatever you can come up with that still ends with something close to the canon personality is perfectly acceptable!