Air 9 RDO
I have a Wheel's Mfg. EBB. Fits very snug, I had to use a BB press at first use, now it's more loose. Problem Solvers also makes this EBB and of course Niner has their own version as well. I found mine to be the least expensive...
I got some spacers from Endless Biking at NC, and the wheels are I9, the bike feels totally awesome!
I used to have an earlier Carbon Air 9 when they had skewers... the rear wheel tended to become disaligned, not with the new setup though