I have tried a bunch of pocket holsters for the PM9.
I have come to prefer the simple and cheap. (I feel just the opposite for belt-holsters).
My remarks refer to front-pocket carry. I can't comment on rear-pocket carry.
The well crafted, finely formed leather ones are nice. But these require "top hooks" or side wings (or both) that are designed to snag on the pocket when drawing. So the holster comes up with the gun until it breaks away (like a launch rocket) when the pistol nears the top of the pocket. They are also rigid and tend to print more than fabric holsters. They are more expensive. The DM Bullard is a nice one, as is the RGrizzle and the RKBA. In kydex, the Aholster is well molded to the gun and also to the contours of the leg. Look for leather holsters that appear better shaped to the contour of the leg. These kinds of holsters probably do better for tighter fitting pants, such as jeans. Any pocket holster does well enough in looser fitting pants such as cargos or slacks or in jackets.
The simple ones like the Mika, the Desantis and the High Noon are thicker and rely on a loose fit and grippy material sewn on the outside to separate themselves from the pistol when drawing. This separation usually occurs right away at the bottom of the pocket. Since they are of soft fabric rather than hard leather, they print less and mold to the leg easier. Since "retention" is not an issue with pocket carry, a tight fit is neither necessary nor especially desirable. One hand re-holstering and a rigid top opening is not much of a concern either.
You need to decide if you want your sights protected or not (by leather or fabric), as some models do and some don't.