I phoned customer support this week to ask that very question. They stated that the version for the X920BT is not available yet. I asked for a timeline and got the "it will be available in 2 weeks" answer. I think that's a standard Pioneer reply when it comes to release of supporting software.
I noticed on another post dated April 5th that the Pandora Link software and Music Sphere software was going to be out in 2 weeks also (still not available). I asked the customer support person about those as well and got the same "it will be available in 2 weeks" answer.