Having owned both, out of the box the N9's camera is far better than the N900's, in low light and generous light. There isn't really anything to argue about there. With Bless900/Fcam that may be different, but it's impossible to fairly judge since neither is available for the N9.

As has been said earlier in the thread, the N9 does have trouble with exposure in less-than-bright light; this can be clearly seen in its tendency to blow out low-light images with its own flash.

I'm definitely not a photography expert so I am probably wrong here, but might the OP's examples be partially due to the N9s larger lens? Taking a direct photo of a bright and close light source in a dark room seems like a pretty reliable way to overexpose a shot.