I agree with Devonlad.
Never turn your back on a tup - which is what your sheep is now, not a lamb.
Don't feed tups with extra concentrates unless the weather is very severe - hay and a mineral lick are fine
You have to be the dominant one and he has to know it.
Carrying a long stick helps - definitely not to hit the sheep, but to hold the stick above your head, which makes it seem to him that you have a much larger set of horns than he does, so he won't challenge - might be too late for that to work.
A ram is not your friend nor your pet.
With young children thinking of him as a pet, injuries will occur.
Castration will help but he's already had a hefty dose of testosterone.
If you breed, or buy in, more male lambs this year, it's best to have them castrated in the first week of life.
Edited to add: a bit indelicate this, but we're all farmers here and half of us are women - a menstruating woman is of particular interest to a ram, and he definitely won't be gentle when he adds you to his 'harem', so that's an extra reason for you and your family to get rid of the lad.
In your original post, you say 'one of our ram lambs..' so, you have more than one. Even if the others appear gentle, submissive, as soon as the top tup goes, another will rise to take his place. There's no point in waiting to see if this happens, you just need to deal with it now. Children have to learn at some point that life on a farm/smallholding can be tough and safety comes first.