Hi!
We have had this problem as well, but I think we have found a solution. We do start at 9:30 am (directly after the 8:30 service ends) and have a time of music playing in the background, treats provided (some kids don't get breakfast so a healthy snack keeps the energy up) and then we do group singing (sometimes with hand held insturments) a group prayer and offering until 10:00. I (Sunday School Director) announce each week who is going where and each group of students follows the Shepherd & teacher to the classroom. I do not have a teaching position myself, so that I can assist late arrivals to where they need to go, give an extra hand to teachers as needed and most importantly, help the parents FIND their child when the class time is over. So far, it is working well!
Best wishes!

Heidi Jo