is it possible to play 2 separate midi devices(both usb) with sonar?
 
i want to use a pad control and a keyboard so as to play live

Yes, no problem.

Yes, just be aware of channel assignments and track channel assignments you are using.

I have used 3 midi controllers with Sonar for a number of years now, and NEVER have issues with them.
 
For playing live, you have to be sure to set up the correct midi channels for whichever sounds you want from each device, but that's about it, other than playing the right notes (avoid accidental jazz).
 
Bob Bone
 

yeah... many years back I saw an entire band powered by cakewalk software. It was sending to a bunch of midi modules for everything on the stage.  2 live players with guitar and bass with everything else including the FX modules being midi. Quite a professional set up for the day.... early 90's IIRC.