Presently? Depends.
Usually Rem 124gr +P HPJ/BJHP (Golden Sabre, non-bonded), or Win 147gr RA9T (T-Series) or 127gr +P+ RA9TA. All have been issued loads and are still available.
In the future? Well, due to ongoing ammunition production & delivery problems, the next options in inventory appear to be both Win 124gr +P RA9124TP (T-Series) and one of the Federal 9mm HST bullet weights (didn't look too closely at the cases, yet). Either would do, I expect.
In the past? Just depended on whatever was available at contract or non-contract LE pricing, or approved for personal purchase OTC at some store. I've used 115gr, 124gr, 125gr, 125gr & 147gr JHP's at one time or another, with some of the different loads rated at +P & +P+, depending.
As long as whatever I'm using is new factory ammunition, made by one or another if the handful of major American ammunition companies who are experienced at developing and making good quality defensive ammunition tested for major LE or private citizen use ... I'm not necessarily overly fussy.
I prefer to use one of the newer designed hollowpoints that better resist plugging and exhibit robust expansion in the difficult 4-layer denim testing.
While I'm not particularly interested in "bonded" HP's for the sake of them being "bonded", I'm not opposed to a bonded design as long as it will still robustly expand in heavy cloth/4-layer denim testing conditions. I prefer not to sacrifice expansion for some perceived "better performance" in one of the hard intermediate barrier tests.
I prefer to use ammunition with better quality components other than just bullets, too (cases, powders, primers, sealants, etc).
Whatever I'm using, I want for it to feed, fire & function properly in my 9's, when I'm shooting them.