The 9mm failed to reach the heart on a 6'-1"" 170 pound felon. That's a failure in my book.
^^^This^^^ Speaks volumes to me.
I'll stick with my 45acp or, if I feel the need for more rounds, one of my Glocks in .357 sig or 10mm.
I've personally seen a bonded .223 load (the same load that I shot end to end on several hogs) fail to penetrate to a guy's heart after passing through his left arm.
Stuff happens. And samples of one, or even a few, aren't valid. That's why I give weight to a study that considered an enormous amount of data rather than "well, one time....." stories.