[Stardust]

What do you mean playing up? There is no such thing as playing up, a High School student athlete is eligible to play at any level with the exception of sophomore-senior playing a registered Freshman sport, or a Senior playing below varsity.

If you mean a Middle School athlete playing HS sports, there is no restriction from KHSAA.

In both of these instances, there are school guidelines. i.e. many schools will not allow middle-school athletes compete on HS teams. But there is no state rule on it.