I would recommend a VAC preamp and a VAC PA100 amp which you should be able to purchase for about three grand. This combo drives N802's admirably well and should mate well with your 9NT's. The VAC gear is very well made, reliable, and excellent sounding. Tube rolling can tailor the amp to your preferences.
Tube amp/preamp for B&W CDM 9NTs
I'm considering upgrading to separates but want to keep my CDM 9NTs. I'm running a Marantz SR8000 now but decided to move strictly to 2-channel audio. My budget is around $3k. I'm also open to a good integrated. If you have suggestions outside of tubes, I'd like to hear them too. FYI, the B&Ws are rated at 90dB sensitivity. Thanks! Bob