FAT, PSP, and TUS do 200 only flying I believe. I could be wrong on that though. PHX has mostly 200 with a little bit of 900.
I think SEA and PDX mostly do 700 stuff. I'm not sure if they do much 200/900 flying.
All CRJ crews are qualified to fly the 200/700. I'm not sure everyone is checked out on the 900 though. (it's just a line check)