hypothetically, if you had a legal silencer, any 9mm round would work, I wouldnt wanna throw +p rounds through it, but regular rounds would be ok, but the silencer would be much more effective with subsonic ammo.
http://www.ammoman.com/webstore_9mm.htm
4th item down.
I'd go into detail about how dangerous a home made supressor could be, but this is purely hypothetical, so theres no need.