Preparing son for his first bed.

Hi just seeking any advice with getting my 1yo into different sleeping arrangements.
My son is a great sleeper at night in his cot. Bed at 8pm with the help of two bottles of milk (he is a bit of a guts) and wakes up anytime after 9am. His 2yo sister is in the same room in a single bed. Her bed time is at 8.30pm and she is up anytime after 8.30am.
Nap time is only for my son who HAS to be in his cot, in his room. If anywhere else-he has a lot of trouble falling asleep. This makes it hard to take them to other of peoples places-even those with a cot and a quiet room.
When in the cot, I will always find him squashed up to the side and when he wakes up he will have imprints of the cot mesh (port-a-cot) on his forehead or cheek or wherever he had been lying.
Have attempted soooo many times to get him to sleep in a bed with me or his dad (when sick) or grandparents on sleepovers-but all struggle to get him to relax. He could be exhausted but will still hunt for a place to nestle his head/body. I have even tried to get him to nap in his sisters bed (when so tired he should have had just fallen asleep mid-bottle) but that also failed.
He is an extremely active kid, even when he's asleep. Tossing and turning constantly throughout the night.

he is getting to big now for the cot and will soon be able to climb out of it-but I have no idea on where to go from here. His sister was very easy "this is your bed, you sleep here" but I don't believe it will be that easy for my son.
If anyone has had a similar experience that could help me prepare him for his own bed I would really appreciate any feedback.

Thank you in advance!