NO! do not offer to pick him up! you will get in over your head, picture yourself standing there with all the other kids waiting for this kid to stop the "fit" so mom can finished getting him ready! dont do that \, you will regret it! what you need to do is...next times she drops him off or next time she shows up late with him...very quickly and matter of factly, mention you need him there by the contracted time of 9 am, due to the fact that you usually get the kids out and about at that time and don't want any troubles with outdorr time before picking others up from school.....then, you need to follow through. The next day, you need to have all kids dressed and ready to go by 9 am, IF she is not there by 5 after, GO! go on with your day as if he was there, leave the house go about your regular routine, if she misses you guys? thats her fault......she will learn fast if you dont allow her to control your day. You could even leave a note on the door, "sorry we missed you, left at 9:05, will be ________" thanks _______.