Oh Sorka - I truly hope my DS isn't that clingy at 9! Thankfully DS has always loved bedtime, its just the getting him to stay in there when he wakes in the night that's the issue I have thought about mild anxiety issues in the past, so a psychologist isn't out of the question.

We have implemented a plan tonight...
Basically we had a good talk before bed about how everyone needs sleep and when he comes into our room, nobody can sleep and that's not ok. We told him if he wakes in the night he needs to stay in bed and go back to sleep. If he comes in, we will put him straight back to bed, wait one minute at the door and then go back to bed. Crying or grizzling won't get us to stay. We won't sit or lie on the bed.
He will get a sticker on a special chart if he stays in bed the whole night, and if he gets five stickers on his chart (in a week) we will have morning tea in a cafe. This is a huge deal for him, so fingers crossed. DS has promised to 'try to stay in bed all night', so that's a start.