I've seen epic failures with 9mm on dogs as well! IME a .40 outshines a 9mm on vicious dogs and other large animals and seems to be more humane.I shot a 120lb Rottweiler with a Beretta 21A. He soaked up 6 rounds without even slowing down. The 7th was a contact shot that broke his neck, that stopped him. The first two rounds would most likely have been fatal, but all they did at the time was get his attention off of my 4 year old and on to me.
I'm not much of a fan of.22lr as a fight stopper since then.