Hiya,
I'd just go for it & see what happens - as long as he's in a safe environment, he'll be fine!
We had the same issue with Max (now 8mths) when he was about 4 mths old - he used to sleep in his crate in our room at night but had got to the point where he seemed restless & wanted to stretch out more, so we started leaving his crate door open but our bedroom door shut - lo & behold, he was fine - started venturing out & found a few spots in the room where he liked to sleep & that was it - no problems at all.
Now we even leave our bedroom door open & he has the run of the house - he only ever goes in one of 3 or 4 fave spots & that's it - he sleeps right through the night quite happily - if he does move around, we certainly don't hear him unless he wants us to & then it's a case of him leaping on the bed & shoving his nose in our faces to tell us he either needs a wee or wants to get up & play!!
Sounds like you've got a happy little soul with his own pup-proof room, so I don't think you've got anything to worry about - he'll sleep if he's tired - it might be a novelty for him for a few nights but he'll soon settle.
Good luck!!