I'm in this depressing situation also.

9 month DS wakes up every night at nearly the same time crying. Then when one of us goes in he smiles and is wide awake and wanting to play. Then he screams bloody murder when we leave the room. Read somewhere it could be separation anxiety but not sure how to 'cure' this. We are so tired we just end up putting him in our bed most nights thus simply rewarding his squawks for attention and then we wonder where we are going wrong

We're in exactly the same situation with our 9 1/2 mo DS. Not sure if teething - as with you we didn't have too much trouble with his 1st 2 bottom teeth. Maybe the upper set are more painful? Wasn't helped by picking up a vomiting bug 2 weeks ago - since then he's been really unsettled both at night and in the day - constantly wanting cuddles or more often than not a BF.
Also he didn't ever really cry and now he howls. not much help - sorry - hope someone else can give advice?

We have always been lucky with my DDs sleeping as she has slept through since 2 month old but now at 9 months for the last 2 weeks she has begun to wake at night crying and screaming and we are only able to settle her by cuddling back to sleep some nights i am up nearly every hr doing this. Not sure what the problem is, could be teething but she only had a couple of poor nights with her first two teeth. Could anything else be causing this and any suggestions to help would be gratefully received.