Well merde ... You can't be expected to do nothing after 8:30 pm ... That's just absolutely unreasonable. And that's usually a time at which people are still having dinner in France !

Why not just stay in the main part of the house until he's asleep? You don't have to go by his door and can access the bathroom and rest of the house. It's a win-win

walk quietly?

Omg this reminds me of this person from my sisters 'in laws'. He has a 3 year old child and no one in the house is allowed to make any kind of noise after 7pm incase the child wakes up. Everyone has to stay quiet until he wakes up. It's actually really weird because once my sister had to stand infront of the window until someone opened up the door for her, all because the child was asleep.

I know this is a crazy idea. but close the door?

Make them close his door. Can't be tempted if he can't see you.

That's a bit much. I shared a room with my two sisters, we each had a different bedtime with no issues.

It's the same at my house with my brother, OP.

That's utter bullshit, do what ya want and force them to get up and confront you every time, or piss in a bottle and leave one outside their door every night.

If his room is closer to the bathroom switch rooms with your brother.