My youngest dc is on the 99.6 centile for height. I don't know how much he weighs, but he looks lean, appropriately muscled, and proportionate. He has almost always been on or above the 99.6 centile.
In other words, he looks about 2.5 years older than his age: 9 or 10, rather than 7.
My question is, does he have the same physical abilities as a 9 or 10 year old? I can't really compare him with his big brother because dc1 is 'behind' physically (he is very pleased to have at last achieved a 4c in PE - in Y8).
I think you'd have to compare him to another 9 or 10 year old! My DD is very similar and in some ways she is physically more able than her peers but not in other ways. She has the strength of a 9/10 year old but not necessarily the co-ordination. She also doesn't have the confidence in her own abilities that come with age.
Sports she does well at are things like swimming and gymnastics, sports she does less well at tend to be ball sports and similar.
No, he won't be the same, he won't have as many years of motor skill development and he won't have the same ratio of muscle mass to rest of body mass (on avg). His head is still larger compared to rest of his body than a 9-10yo which affects things like his balance, too.