Bossy older sibling

My 9 year old son consistently feels he can boss around his younger sister (age 6). We have given all sorts of corrections …extra chores, SODAs, talking about roles, talking about who he wants to be and using self government to become that person. He does get lectures mixed in the with TSG skills as we’re still trying to unify as a couple / wrap our minds around TSG.

It’s worse in the mornings or after a long day at school. So when he’s most tired.

It’s definitely a role issue (at least in part) and him disrespecting us as the leaders in the home… I’m not sure what I’m missing …