Rob,
I currently own a very similar setup.
SP 1.7, 6B SST, 4B SST, 3B SST
5 x TB2's, 2 x TB1's
a "few" non PMC subs.
My room is 13.5 * 24 * 7.5 also in the basement. You will not have to worry about volume with the TB2's. My TB2's play plenty loud. I tried to see how loud they could play with my 3B SST by cranking it till the amp clipped and trust me it was excruciating loud. The 9B SST has just a little less power than the 3B SST so you should be fine. I also considered active speakers at one time.
The active TB2's do not use Bryston amplification but instead Flying Mole which I believe is a digital amplifier. Although I never listened to the TB2S Actives, I would wager the passive TB2 with SST amps will sound better. The active version of the TB2 is basically an amp bolted on the back of the speaker as opposed to using an electronic xover and two amplifiers which is how Active Speakers are usually defined. If you want to save amplifier space on the rack by going active, I would consider getting some Bryston PowerPac's and bolt those on the back of the TB2's but this will be much more expensive than a 9B SST.
The amplifier with passive speakers will provide you more flexibility when you want to upgrade as there are a heck of lot more passive speakers available then active. The reason why I purchased the powerhouse 4B and 6B is that I do plan to upgrade to bigger PMC speakers sometime in the future (ie when I move to a bigger house).
The only concern I see with your setup is the sub. I have never heard the TLE1 but it may not provide you with the deep subsonic bass that you may want eg sub 20 hz or the spl required for your room. If you are not a basshead no worries. But once you have felt controlled sub 20 Hz bass - with decent spl's there is no going back. It is really the sub that will fill your room with sound.
