I have to ask, do you really want him to 'learn' to 'listen' to adults who are so in the dark about who he is as a person?
I think he's already showing with his behavior that he has learned all he needs to learn about being unseen by important adults.
Actually, I think that the older of his two teachers knows he's "advanced", if not gifted. She and I have had a couple of conversations that indicates she knows we have him there for learning to get along well with others. We've offered to send him with some workbook pages and they have said they appreciate that offer, but so far, he's being kept busy with activities.
If it weren't for that teacher's comments to me about homeschooling him, and how "smart" he is, I would wonder the same thing, Grinty.
It's still only October, so who knows what's down the road? His reticence about sharing his day may morph into something else entirely later.