Maybe. It’ll be fine, unless you break a bolt catch or whore out that pocket in the lower. I’m not sure how common that still is.
Yes. I’ve used a Griffin 3-prong on an 8.5” barrel 9mm. An adequately long silencer would help, also. Of course, the flash without one isn’t huge (consider the humble Glock), and a 1.25”-1.75” longer barrel would be just as reasonable a choice compared to any 9mm muzzle device. Powder or ammo selection goes a long way. For example, Titegroup is thermonuclear in comparison to CFE-P.