Yes, a 9mm will take down a hog if you’re holding four aces and have an angel in your pocket. I know one individual who killed a charging grizzly with a 9mm, but just because you can do something doesn’t mean you should. Ethical hunters have an obligation to use enough gun to achieve quick, humane kills, and 9mm is a poor choice for the job. A friend once emptied a .45 ACP magazine into a hog without putting it down. I once followed up a wounded hog and shot it between the eyes with a .44 Mag. The round bounced off the skull, and I had to put another one behind the ear as it ran past me. If these cartridges didn’t get the job done, the odds with a 9mm are not in your favor.