Hand the ball to the referee and jump all you want. It’s a delay of game to hold on to the ball....Sorry those are the rules.
Some players run all the way to the corner of the endzone, despite the play being over at the line. Is that also delay of game? Its holding onto the ball, right? What about players that walk the ball over to the referee or drop it? Dropping is considered relinquishing and that can be done a long way from a referee. Is that also delay of game? What if they jump, dance or pray, while moving toward the ref with the ball?
Its an ill defined rule left open to the subjective judgment of the official. With that in mind, the official's subjective decision is also open to everyone's subjective judgment.
As I said before, delay of game in the case of post touch down action requires that the game actually be delayed by a failure to relinguish the ball. Kneeling with the ball for 3 seconds and then running it to the ref is no more delaying than simply dropping the ball at the back of the end zone. So the penalty was for an action, not for a delay. Right?
If I'm the coach, I tell the kid to drop the ball next time before he kneels and to keep it to 3 seconds or less. If the player is back on his side before the kick, you have no penalty.