Although I've never personally tried using the RMA Babyface Pro, I assume that it just works like a standard USB Audio Interface. In this case, you can actually create an Aggregate device between the H9000 and the RMA Babyface. At this point, you would have to make sure that your assignments are correct and that the 'Main Outputs' are routed onto your RMA Babyface. Once all your routing is set, you can now use the H9000's USB Audio as hardware inserts onto any tracks giving you up to 16 ins/outs.
If you need help setting up the unit, please contact me at Pflores@eventide.com
Hope this helps!