I read your post with great interest because while I absolutely love my XD-40-sc, it feels too big to cc (I'm small). I ran 50 rounds through a rented P9 today (second time I've done this) and really like that gun, especially for cc. I'm glad to hear about the grip ext because even though I have awfully small hands, the grip is pretty short. It bounced around a little in my grip, but not enough to make me feel insecure that I'd drop it. And it made me look good regarding what the target looked like at 20 feet. Plus, I'm able to shoot it off-handed without much recoil compared to the xd.
Question, I find the aggressive bumps on the grip a bit painful for skin on my hands. (I literally get indentations from it) Do you think a Hogue rubber grip would fit over the grip?
In any event, I'm going to start my search for a used one too.