A big problem I always had with this game is that I just loved waaaay too many characters to bring em. So I'm wondering if there is a mod that could increase the party cap of 6 to like 9?

Nope, at least I never seen one in 10 yrs of lurking everywhere BG mods are ...

check the bodies does...but you have no control (they acti like summons). I've never heard of one, I've been told impossible, a game engine limitation.

I've always wanted this as well but I believe that would break game balance. I think part of the fun is making a good balanced party with interesting characters.