AIBU to expect DH to come to bed at a reasonable time?

You dont need to be policing another adults bedtime.

She isnt going to bed to sleep at 9pm. She is just stopping looking at a screen at that time.

how are we supposed to be intimate if he won't come to bed??
Is this the actual issue?

As long as he’s not waking you up when he comes to bed then he’s an adult and can go to bed when he pleases.

I can see both sides as I would be annoyed at a partner needing to be in bed at 9pm every night and would feel like I was spending my evenings alone. Has he ever asked you to stay up later?

We go to bed at different times. Mostly I go up first but sometimes DH does. I have realised that I need to wind down alone.

I would be annoyed if I had to go to bed at the same time as DH.

DH does this too, we have opposing sleep patterns. I recall once going to look for him at around 3AM, and found him in front of his computer in his dark office - and as soon as he saw me he started frantically closing all the work spreadsheets he was working on. I just said, "Why can't you be looking at porn like everyone else?"

Anyhow, we solved the problem years ago by sleeping in separate floors rooms, so him coming to bed late doesn't disturb me. I recommend it, we're both less stressed.

DH and I are living apart at the moment. It's only temporary and I will see him next week in Spain to collect my residencia, then 3 months over Xmas, moving out finally next March.
Even when we are in the same place we go to bed at different times.
He's a night owl, I like to be up and about by 06.00.
Horses for courses

He doesn’t want to go to bed at the same time as you which is his choice. How would you feel if he said you had to stay up with him until he’s ready to go up?
I like to go to bed early and read. My other half does not. It gives him chance ti watch shows on TV that I’m not interested in. It’s fine and works for us both.

You say you spoke with him about it: what did he say? Does he feel rested enough, if he has to get up at the same time as you? Does he understand that you miss him and would like him to be in bed with you? Does he see it as a problem? Did he say he’d stop just to get you off his back?

DH and I don’t always go to bed at exactly the same time but neither of us would function well falling asleep on the sofa then going to bed really late. It’s not giving him a good nights sleep. Starting to fall asleep on the sofa is a signal to get to bed, for me.

I agree with @FlorenceLawrence
Do you think there is more to this than him just accidently falling asleep.on the sofa?
If the same pattern is happening every night it does seem like you are both missing out on the opportunity for closeness and companionship.
Perhaps you could both talk about this. Perhap you could vary your routine a bit and some nights sit up a bit later with him because you seem quite rigid in your habits too?

This, there seems to be this thing on mn where men juat have to do whatever their partner decides for them

Remind him now and again that you miss him in bed with you.
Ask if he would feel like coming up earlier if you were ready for sleep earlier?
It could be that he is tired but you are awake.

More likely, though, that he has developed a bad habit of winding down by watching tv until he snoozes.

Are there any issues in your marriage? Is he avoiding for some reason? Or up to something on his phone when he "accidentally" falls asleep on the sofa?
It's a segregation in your married life - I would want to explore why.

I guess he thinks you go to bed too early & knows you read etc…. Then he probably
just nods off because he’s down there alone… I think as long as when he does come up he doesn’t disturb you I would leave him down on the sofa….. after a
few nights of you leaving him down there all night he would soon realise his back is suffering as hopefully take steps to ensure he gets up to bed… you can only but try.

We never go to bed at the same time. Married 16 years. Dh is exactly the same as your dh. I am usually in bed by 11pm and like to read quietly before I go to sleep. I’m actually glad he doesn’t come to bed at the same time as me! (I’m unusually awake now because I’m not well).

He’s not a child and can go to bed whenever suits him.

People 'wind down' differently.

You've discussed it with him and he has said he will try to do what you've asked; that doesn't mean starting tonight and every night thereafter.

I don't think making someone go to bed is the way forward.