A simple passing drill that can be fun.

Put an uneven number of player's in this case 9, in a circle.

Give a ball to player 1 and 9 and let them pass to the right skipping one player.

So the pass sequence will be 1-3-5-7-9-2-4-6-8-1 or 9-2-4-6-8-1-3-5-7-9 depending on your starting point.

The goal is for one ball to overtake the other.

As this might be a bit dull the following variations are possible:
Add balls up to 9 shouldn't be a problem.
Change direction from anti-clockwise to clockwise on a signal.