Our dear daughter will be 8 years old by cruise time and she too has an early bedtime (her choice). If she stays awake too late she'll be a zombie the next day - and she's got an internal clock that doesn't allow her to sleep in!
Since it's just the three of us, I know that our room (on the Pride) will not have the "upper", but it does have the convertible sofa. If we have the TV on quietly, she'll fall asleep and then she's pretty much 'out' like a light for the night.
As for nights that we'd like to go out and enjoy the evening activities, I'm still tossing around the idea of hiring a ship babysitter. I'm still evaulting my personal comfort level regarding a complete stranger being in our stateroom unsupervised - let alone watching our only child unsupervised.
But back to the sleeping arrangements - it's too bad they don't have some sort of screen separator that can pull down to provide some shade and privacy. I'll be curious to see if any other cruisers with children have come across our situation and be able to provide suggestions.