All handguns are relatively poor "stoppers" regardless of caliber or bullet used. Shot placement and sufficient penetration are paramount, all else is secondary.
Bottom line: choose whichever caliber you shoot the best but I prefer the 9 for greater capacity & less recoil for faster followup shots.
"Among other evils which being unarmed brings you, it causes you to be despised." - Niccolo Machiavelli