I was under the impression that the military had given up the idea of replacing the M9. Apparently not, according to Military.com:

The Air Force had asked for $90 million in the 2007 supplemental to buy new, more powerful pistols. Instead, congressional negotiators appropriated $5 million for a joint study on a new combat pistol, with the Army as the lead agent.

The US Army and Navy have recently purchased more M9 pistols.

More here.