The 9mm is really popular again, and will likely remain so until there's another high profile failure.
The bullet that a coroner determined to be the primary cause of Michael Platt's death in the 1986 Miami shootout - was the 9mm Silvertip fired by agent Jerry Dove.
Yes, the much-maligned 9mm Silvertip, created a wound in Michael Lee Platt that the coroner determined Platt wouldn't have survived even if he'd received immediate medical attention.
The issue with the 9mm round in the 1986 Miami Shootout was not an issue of bullet weight or caliber, a failure of the bullet or a failed bullet design. The issue was that of proper requirements.
The Winchester Silvertip performed the way it was designed, the primary requirement that it was supposed to meet was to not over-penetrate, and the Silvertip didn't over-penetrate.
The main failure in that situation is that the agents were equipped with a bullet designed primarily not to over penetrate when they needed bullets which penetrated 12" - 14" through various barriers (criteria the FBI later developed).
If instead of switching to 9mm, the FBI had switched to 38 Super, and then put forth as their primary criteria that the round not over-penetrate, the results would have been the same. Platt would have been hit with a round that was designed to expand rapidly and not a round designed to penetrate.
If Jerry Dove had been shooting 9mm FMJ Michael Platt would have died instantly. But the FBI didn't want their agents to have 9mm FMJ as was evidenced by the fact that they issued them Winchester Silvertips.
It seems like an awfully constrained decision making process if you start off with "38 Super vs 9mm." There are hundreds of different 9mm guns of different shapes sizes and weights with all sorts of different features and controls. There are 9mm pocket pistols, I'm not aware of anyone making 38 Super Pocket Pistol. There are other considerations like how it fits you, how it feels in the hand, how well you work the controls, how you like the trigger etc... You're only going to find a few models of guns chambered in 38 Super.
For me, I pocket carry a 9mm, my truck gun is 9mm, my nightstand gun is 9mm, it just makes things simple and I don't have to stock different calibers. But that's just me...