I can't say for certain, but I think it's highly unlikely that there's an editor for this game. If you're only concerned with alter boss and enemy HP then the project shouldn't be extremely difficult. I say shouldn't because there's always the chance that information is compressed or stored in a way that makes access extremely difficult.
I don't know anything about psp emulation, or what emulator has a tracer, but if you find one that does, then that's going to be the first step (after learning about hex and the basics).
One thing to note though is, that to my knowledge, the game doesn't run properly on emulators. If this is still the case then that's going to make things harder than it's probably worth at this point, particularly if this is your first project.