Just like univibe posted, it is all about plecement and penetration. I carry for SD what I can shoot accurately. Now, ammo companies have improved their loads for modern 9mm. My go-to's for my 9's are the Federal Punch 124gr JHP (my SCCY and my P365), and Winchester Active Duty M1152 115 gr FMJFP (for my 6906). I trust that they will work, and they shoot to where the sights are pointed.
20-30 years ago, it was which 38/357 would work. Most were not as accurate as the 9's today, other than 38 HBWC's (which have never really changed), and 38/357 LSWCHP (which haven't changed much, but were only really accurate via handloading - for me).