It’s about coaching too- a few clubs want them playing a particular way.
It’s always been the case from U9, but the FA changed it to U12s a few years back, at the academies discretion. The worst practice is when they won’t retain, but refuse to release without compo, then you’ve got kids kept in purgatory.
He’ll still be allowed to play representative football for school district etc, which I dunno if Salford Schoolboys will have a Year 7 team, usually runs from Years 8-10