It wouldnt be able to work with a 9mm bolt. It would have to be an ar15 bcg with a 5.45 bolt face. That will reliably seat a 9mm every time. You would then need a cmg 9mm delayed blowback barrel. Essentially it would be the same setup as an ar15 but with a 5.45 bolt face and cmg 9mm barrel. The only problem would be ejection. I have this setup with a BCA bolt upper on my an ar15 lower. I use printed mags. It works but because its still using the ar15 ejector and the 9mm casing is shorter it ejects into the receiver instead of out. I have tried figuring out how to make it work flawlessly but still havent found a way. The only way I see it working would be to cut the BCG into shape of a 9mm bolt to allow a 9mm magazine ejector, or after cutting the bcg you could add a permanent ejector inside the upper receiver.

I might try to build this around the 9mm and see how ejection works because with my bolt setup it eject decently if I rip the bolt back. With a lever it might actually be more reliable.