FWIW - you are right on the bedtime argument but being right won't help. Children at the age of six still need a bedtime closer to 8/8:30. Some may need to go to bed as early as 7:30. Any teacher, psychologist, pediatrician would agree. The only exceptions would be a child who was homeschooled and was allowed to wake up later so they could get an appropriate number of hours of sleep.
I think your best bet would be for BOTH of you to schedule an appointment with the teacher to discuss the behavior stuff. Believe me she will recommend sufficient sleep and she may offer some other insights too. That way it isn't just you. You should say very little other than "Mmmmmhmmm. What do you think, Mr. H?" "What other suggestions do you have Mrs. Jones?"
I also think that your H uses keeping the children up late as an excuse to distance himself from you. I think he has done it for a long time. It is handy because it sets him up as the "cool" parent thereby guaranteeing that he will be preferred by the kids AND keeping your alone time together to a bare minimum. That being the case, if you get to a point where you can actually discuss this subject with some spirit of cooperation you can point out the need for some alone time if you are to try to work on this M.
First, he has to agree to work on the M. Good luck.
