I've yet to listen to them with the grills on. The dealer had them off so I just kept them off.
I've heard the D9s with a Chord DAC and they go very well together. I'm using a SimAudio 380 DSD DAC which I think has the similar musical and non fatiguing sound like the Chord DACs. I replaced a Berkeley Alpha 2 which I found a little too detailed/analytical with my previous Magico S1s, but I wonder if it wouldn't pair nice with the D9s which are a little more forgiving.
Yes, other than the amazing mid range, their punch and deep bass is what really surprised me. I was expecting a polite and highly refined speaker and I was taken back by their ability to really boogie. In that regard they remind me of the Revel F52s I had before buying the S1s.
Do you have them setup with any toe-in? I have them at 12 degrees (using a phone app) which translates to slightly behind my listening position. HiFi World has a recent review of the D9 and they recommend no toe-in as they found the treble a little too prominent. Since I am coming from Magicos I don't find their treble too prominent at all... I'm using a Pass X250.8 amp which along with the SimAudio DAC make for a pretty relaxed sound.
Checkout the HiFi+ review of the D9s if you have not already, it is a pretty good read...
Cheers