9mm is so un-american, quintessentially.
.45ACP will always be THE US calibre for pistols - period - full stop - end of discussion.
There are still legions of folk in the states (and on here, for some weird reason), who live, breathe, eat, poop, dream, fondle, etc. ONLY the Colt 1911A1, and even if they are tactful enough to not open their mouths to express an opinion, basically believe that 9mm in a handgun is only for folks who "squat to pee".
That said, I'd concur that the S&W 39 was the first legitimate 9mm pistol made by the Yanks. The BHP would have been, but alas became, in my opinion, a European device, when first made in Belgium.
Probably the first import to make any useful waves would be the Sig P220, when brought into the Joint Service trials (that the Beretta won, somehow), and was subsequently adopted by a few law enforcement agencies.
Glocks then, of course, hit the market, did some great marketing, at a great price point, and the entire world bought them up... Because agencies will always buy cheap over quality, IMHO...
Just my random ramblings on the topic.....