Baby steps for Ads and some advice needed for Y

I'd posted just a fortnight ago about Ads being afraid of being left alone at the bus-stop. And yes, yet again, my children have surprised me by behaving out of character (maybe that is in character?!!) Because the mornings are so hectic, with Ads' bus arriving at 7.20 am and Y needing to board her van at 7.40 am, Ads has started walking alone to the stop (which is just outside the main gate of our complex so he doesn't have to cross the road). Most days, S or I follow him to his stop within 5-10 minutes, with Y in tow, and we are there to see him board the bus. This is because the bus sometimes arrives only around 7.30 or 7.35. But on the days it is on time (like today), we haven't been able to make it because we are still getting kid#2 ready for school. I feel a little bad about Ads going alone but he doesn't mind. He's proud that he goes to tennis class all by himself and gets back home after playing in the park, again by himself. These small steps towards independence mean a lot to him, as they do to me. In any case, I am usually around whenever he is down, just in a different place; for example in the children's play area with Y while he is in the lawn with his friends. It helps that the complex is quite secure, tons of guards everywhere, lots of kids/maids and the security staff in general is quite alert and seem to know all the kids. 

He has prohibited me from picking him up from the bus-stop at 2.45 pm, but this is something I said no to. Primarily because, once he fell asleep on the way home and the bus-driver and the bhaiyya did not realize that he had not got down. They were all ready to speed away but then saw me waiting and realized a kid was missing! Since that incident, I have lost a little of my confidence in them. So I go to the stop and wait anyways, risking Ads' annoyance on seeing me! I'd much rather not have to pick him up because I'm forced to leave a sleeping Y alone at home when I am downstairs, but at the moment I don't have any backup.

In the meantime, our old problem has resurfaced. The class teacher at Y's new school has been telling me of almost-daily episodes involving Y hitting other kids. Today, she has bitten some child. I've been feeling really upset because, believe me, I've been on the other side of the fence and I know how it feels when your child tells you that some rowdy element in class hit/bit him:( I've been talking to Y and this afternoon she was visibly angry with me (probably because I kept harping on the same theme). Any good ideas on how to explain to her that hitting/biting/shoving is NOT okay? Her teacher seems a little inexperienced and I get the sense that she's a little out of her depth in handling this. In Y's earlier Noida school, the teachers were very savvy and managed to resolve this issue in no time. I've asked S to talk to her too, and hopefully she will understand why it's hurtful to cause pain to others.