I coach a JV team, and nothing I tried has worked. They don't listen and they all just cram up the middle of the field and play kickball. We had a scrimmage yesterday and I told them 15 times to stop playing kickball and start playing soccer, and it got to the point where I had to start having players do goal post to goal post sprints every time they kicked the ball just to kick the ball. Don't care if the drills are boring as long as they are effective.
At that age and limited amount of time to coach them, you're pretty much fucked. It'll probably take a few ass beatings by some teams that can somewhat possess the ball for them to realize, but then they probably have zero first touch and no concept of movement. You're best bet is to start with some type of small sided games with no goals.
I love it when you see an 8/9 year old who just gets how to play, you can just tell how manipulate the ball they keep good possession, they dribble closely, they switch the field, they pass into the corners of the goal instead of just kicking it as hard as they can it just makes me happy, the club I coach at has about 80 u10 boys, and there are only 4 or 5 that are like this /swoon
I'm not sure how many kids you have but group them into a small space with 2 teams and play "keep away". Anytime a team kicks the ball out of the boundaries or turns the ball over make them do 5 updowns and then continue the game only the other team now has the ball. It will teach them how to short pass and how to play disciplined. It will also improve your defense.