I understand the derailleur pull ratio has been matched to the DA 9000 shifters, but I don't think that would be much of a problem as the shifter type controls the pull ratio.
I've seen people mix 9 and 10 speeds. But I think you're better off getting matching sets than experimenting.
Thats because 9 and 10 speed shifters share the same pull ratio, where as 11 speed shifters pull a different amount of cable. The anchor point of the RD is different as well leading to no compatibility.