Illegal Sub/Participation/Formation?

[waltjp]

Sorry guys, at work without my rule books.

NFHS

Team K is in punt formation at K40. K has only 10 players on the field as the RFP is blown. K80 steps from his team box onto the field.

Sit A - K80 stops after a few steps but still inside the 9-yard marks. Team R doesn't notice K80 and nobody covers him.

Sit B - K80 stops after a few steps but still inside the 9-yard marks. Team R does notice K80 and cover him.

I'm thinking Illegal Participation in Sit A and Illegal Formation in Sit B. Case book or rule reference would be appreciated.

Thanks