Both my duty gun S&W 4566 and my off duty, 4513TSW, are 45 caliber pistols. Every agency in my jurisdiction, locally, has gone to 45's with the exception of the NCSHP and SBI.
I read about "LE agencies move back to 9mm..." but I'm not seeing it, here anyways.
I like the 45 acp. Good round that has a proven track record. I notice that agencies and units that have frequent contact with violent felons all choose pistols chambered for the 45 acp. I find that interesting.
That said, I'm not one of those "45 snobs". Shot placement is the most important factor in using handguns for self defense. Not caliber. Any caliber, 9mm or greater, will serve you well IF you are proficient with the use of the handgun chambered for it.
Buy a gun that fits your hand in a caliber that you can get fast accurate hits with and call it good. I did. And they happened to be 45 caliber pistols.
Regards 18DAI