Josh, If you have the cdj 2000's (which have a built in sound card), I would not trade in a djm2000 for a 900. The DJM2000 has a lot of midi options that would work for you. Perhaps you should consider that route. The DJM 900 is only good for Traktor if you do not have a sound card in your CDJ and if you don't wish to carry an external sound card like the Audio DJ 10.
I traded my DJM2000 for a DJM900 and I can tell you, as a Traktor user, now that I have the CDJ 2000 nxs, I want my DJM2000 back. With the 900, your options are limited and the only benefit that I see, is that your using the built in sound card to operate Traktor in HID mode which you can also do with your CDJ2000's as they have the sound card in them. Just my 2 cents.