OK, with that info....I would stay away from the Dali..at least that model. The problem with them, is if you go for the stuff that is really made in Denmark..the price jumps up like 3 times..so probably not worth the money.
The Kef speakers you mentioned, I have never heard. There a new model. If there is anyway you can go listen to them i would. The older Kef stuff, to me, was to layed back for my taste..but again thats just me. You may love them.
In your room i "assume" you would put the speakers on the 11ft wall and fire them into the 23ft space.
I have my 12's in a 17x30 foot room. They will get VERY loud, and i sit 15 ft back.
In your room, with just the 9's...if you sit lets say 12 feet back, you will probably get blown out of your chair...LOL
Since this is going to be a surround system, and your going to add more speakers plus a sub...this is going to get real loud, real fast.
I would tend to go with the 9's for basic price VS performance..for what you want to do. You may have to throw money at some room treatments, as with a bunch of speakers in that size room, you may have all kinds of problems with sound reflection.