Official comment
There is no timeline on availability of 64bit drivers.
As @lostnthesound notes, as the drivers for the DJM-900NSX2 are 32bit, you can not use a 64bit software as it can't load the drivers.
You will need to use a 32bit application to record from the DJM. If you want to use Traktor, there is a work-around to run Traktor in 32bit mode available here.