In regards to if you can buy Dino Crisis & Dino Crisis 2. Yes you can directly on the PS Vita, PS3 and PSP stores buy the PSOne Classics versions but you cannot on the Playstation Store website because last year just prior to the PS5 launch they removed all the PS3, Vita and PSP games from the website.
Most of the games on those stores are still available to purchase right now, though I did run into an issue on PS3 where the Buy buttons were invisible, selectable but invisible. Some games such as the Danganronpa series have been delisted due to licensing issues and unfortunately never republished.
Also for some reason a bunch of PS One Classics can not be directly downloaded on Vita but can be transferred from PS3.
In regards to Austin thinking about buying a bunch of games just so he has the chance to play them in the future, a problem I ran into with that is that Vita store management has been neglected by publishers so a lot of games never got price drops and never go on sale, which means a lot of games are still listed at their launch prices. Unfortunately there does not seem to be much of a clearance sale effort going on yet.
Personally I ended up grabbing Soul Reaver, FromSoftware’s Shadow Tower, three PS2 Classic versions of the Fatal Frame games and some Harvest Moon games on PSP.
Edit: Oh also if you have Two Factor authentication enabled on your PSN account you need to login to a weird section of their website to get a code to use as a password on the older systems. But there is a bug with transferring PS One Classics from PS3 to Vita so if you want to get Soul Reaver, Metal Gear Solid, Xenogears ect…on your Vita you need to disable Two Factor (and I also had to reset my router to clear some cached data).