I am more of a pocket or OWB guy, but I'll throw my .02 in.
I don't know your build, but if you are the slim type, stay away from any IWB holster that is bulky. It is just impossible to hide on a small frame. As mentioned earlier, the clip mounted to the portion where the gun is makes it too thick to conceal. But on the other hand, I have a Khoster mini-moon (similar to crossbreed concept), but it is almost overkill for the amount of leather and kydex to carry something as small as a CM9. I might as well being packing the Glock. I am still on the search for a low profile IWB for the CM9 that is minimal, but at the same time not bulky. The kydex jfootin showed might work although it doesn't give like leather, and I question hard kydex against my skin for a full day. Even though the clip is on the side, the kydex is only slightly larger than the weapon - keeping it thin.
I would not go ankle as it is hard to get to as mentioned.
Good luck, and let us know what you end up going with.
I ask, sir, what is the militia? It is the whole people, except for a few public officials.
To disarm the people is the best and most effectual way to enslave them.
--George Mason
ΜΟΛΩΝ ΛΑΒΕ
Got that DC?