I would recommend Adrenaline. It has good compatibility and performance when it comes to emulating Vagrant Story on the PS Vita. It can handle the game's mechanics and graphics fairly well. Plus, it's relatively easy to set up compared to some other emulators. So, if you're looking for a smooth emulation experience for Vagrant Story, Adrenaline could be a solid choice.
Well, Vita3K is also a notable emulator for running Vagrant Story on PS Vita. It has been in development and improving over time. It aims to accurately reproduce the game's environment and gameplay. However, it may require some technical knowledge to get it up and running optimally. You might need to adjust settings like resolution and controls to get the best experience for Vagrant Story, but once you do, it can offer a great way to play the game on your PS Vita.
The RetroArch emulator is often considered a great option for playing Vagrant Story on PS Vita. It's highly customizable and can support a wide range of emulation needs.