The best bet in a 9mm compact is a da only single stack compact that will fit easily in your pocket and doesn't need a special holster to carry it in. This eliminates most of the competition your down to a keltec pf9, ruger lc9, or a compact kahr.
While it seems cool to carry a single action 1911 9mm compact, they really aren't that practicle and safe to carry, it also must be carried cocked and locked in a safe belt or outside waist band holster.
Also avoid the striker fire glocks and MP, XD etc. all these pistols must be carried in a holster at all times to safely carry them.
What you really want for ccw is a compact gun that you can carry year round in any type of clothing summer or winter, and that can be safely carried in a pants pocket or small belt or clip style holster. You really don't want a gun that you have to wear special clothing to conceal it.
You will hear a lot from the CCW Rambos that will tell you, that you can conceal any type of gun you want, but in reality there are only a few gun designs and calibers that can be easily carried and concealed for every day use.
Choices usually are 5 shot 38 spl revolvers, compact 9mm single stack DA only autos, and 380 pocket autos, 32acp beretta tom cats, or beretta 22lr SA/ Da auto, taurus also makes some compact autos, but I don't feel that they are that reliable.