This game is a great one for developing both control and aim. It sounds like you're given free rein to whack the ball with a nine-iron, but not so fast. We're leaving out the distance aspect of golf and instead focusing on the part where we make the ball land where we want.
The game is easy. Lay a few used towels (or any other flat object) around the yard. The object is to kick the soccer ball so it stops directly on the "hole." Count how many "strokes" (kicks) it takes to get it there. Whoever has the lowest score at the end of the course wins.
This is a good game for a big backyard space, but remember that accurately passing the ball short distances is a skill, as well. A bonus: You can keep kids occupied for quite a while if the "course" is long enough or if you set up "bunkers" (a lawn chair in the path of the hole) or water hazards (kiddie pools).