I have D9s with a Pass 250.8 and I think the pair sounds excellent together. I find the Pass offers a bit of warmth that goes nice with the neutral-ish sound of the D9 and the soundstage depth the D9 throws with the Pass amp is very nice!
The 250.8 puts out ~25w class A and I've never got the bias meter to move with the D9s at the levels I listen to. If you like the Pass house sound checkout the INT-25 or INT-60. The XA25 really tempts me to try it with the D9, but I run all balanced and it is singled ended only.
I've also tried a Bryston 4B3 and Benchmark AHB2 with the D9s, and both were very good, with the AHB2 making me think for a short moment about selling the big Pass as it sounded excellent with the D9s, not as warm or as rounded as the Pass but incredibly clean (like removing a layer of grease from a window) with great bass control too. I did not find the D9/AHB2 pair sounded bright or forward, just lots of very clean musical detail. For me, the D9s just throw the most life like 3d image with the Pass compared to the other amps I've tried which is why I have kept the Pass amplifier after trying others.
The D9s are such an easy speaker to pair with different amps and get great sound; good choice on speakers! :) Good luck, it shouldn't be hard to find a nice match...