Not strictly 'secondary' I know.. but!
DS1 is almost 10 and in Y5. He's just recently started becoming quite unpleasant at times! Often he's his usual sunny self, then suddenly he's being downright mean to his little brother, almost 8; he's 'gobby'- though that only really goes as far as shouting 'Shut up!' which isn't tolerated in THAT tone of voice; he's becoming unreasonable (he's desperate to sleep in our only family room for some reason, just for a night! I've said Yes in the summer when DH and I can sit in the garden with the brazier on a long, beautiful calm summer's eve, but NOT BEFORE THEN as it's not fair on us- "But that's not fair, you don't always WATCH TV!", implying that I have no right to sit in my own living room with my DH if DS wants to sleep there- then, when I make it clear the discussion's over I'm treated like I've just told him he's banned from his DS for a year- stropping out of the room along with 'Just shut up!'!!)
DH won't handle this at all well (in general). I'm trying to explain that the stirrings of puberty are Magi-mixing DS's brain but DH thinks DS CHOOSES to behave like this. I think he's grappling with feelings he can't yet control, but it doesn't stop it enraging me! And IS 9 a bit young for this to start?? Though a couple of the fellow school-mums tell me similar stories of increasing cheek and unreasonable behaviour!