Child is on the 98th centile for weight - should I be worried? Is this pre puberty weight?

My son is 12, 13 in August. He’s 5’4/5’5 and in the 98th centile for weight.

I want to preface by saying I’m not vocalising any of this to him, but I can’t help feeling concerned as to how it’s happened and whether I need to make some changes with him.

We eat nutritiously, I cook everything from scratch - all our carbs are wholewheat, fruit and veg is always available and encouraged and is eaten with every meal. I don’t buy fizzy drinks. The treats are usually when we’re eating out for an occasion. He walks 40mins to school and back daily often playing football before and after school with friends, swims twice a week in an Olympic pool and football trains once a week alongside general “playing” outside. On paper, he should be a healthy weight for his age but by nhs standards he’s bordering obesity. The only “free reign of whatever food” comes from school dinners and what he chooses. I have always instilled a sense of what is a healthy nutritious plate so he has energy for his sports but I can’t control what the canteen serves and also don’t think one meal a day from there is really an issue.

My thoughts have always been that he’s fresh about to hit puberty and this will likely even out with a growth spurt and change of body composition as most of his weight sits on his stomach and thighs and I understand this is common in pre-puberty but I can’t shift the niggle in my brain that I’m doing something wrong or that there’s something to be concerned about and acting on.

Be gentle, I know weight can be a tricky subject and I’m definitely not trying to make him feel there’s an issue but I need to understand how normal is this really?