If a player falls on the ball (including, on their hands and knees but over the ball), then assuming this is an accident you want to give them a little bit of time to get up. If, within a couple of seconds, they're not vacating the ball or trying to clear it out from under them, then it's an IFK. You're not punishing them for falling over, but just for not letting anybody else play the ball - because nobody can play it without putting that player in danger.
But a few things to consider. Sometimes an opponent will kick that player to get at the ball in the meantime - this will be a DFK against the opponent (of course, higher grades you'll want to see a harder contact before penalising this). Sometimes the ball will be, say, near the player's head and an opponent will take a big swing to kick the ball hard. Very dangerous, and IFK against that opponent (unnecessary amount of force with the big swing right next to the opponent's body).
Another thing - sometimes the player doesn't get up because they can't. When there's a crowd around them, and everybody's trying to get at the ball, the player doesn't feel like they can safely get up. So you may not want to penalise him for that. It could be IFK against the opponents depending how they're playing, or you may want to do a DB. Sometimes a player is trying to clear it from under himself but it's being blocked by the opponents - I can't expect him to not play the ball, so this may be when I go to a DB. Even if I did it at a fairly high grade, I'd just say 'it's not his fault, but it wasn't going to end well' and players will accept it.
Particularly at a low grade/age, I'll be faster to go straight to the DB if I just feel like there's no way it's going to end well. I even do it in adults at Futsal, but that's because most low-grade centres have the informal expectation that playing the ball from the ground is an IFK. So, instead of penalising a player for falling over, I'll just stop it before it happens.
i don't see a problem with the standing bunny hop, as it's easy to kick the ball out from between the legs.
