they don't use the roosting board
They don't use the 'roosting board'
at all - none of them - ever?
8' isn't long enough for 9 birds.
It's enough for them to 'cuddle up' on, but not enough to fly up and get situated.
I would:
Add another roost going across the other way at about the same level.
Make sure both are a foot away from the wall.
Might also be more stable footing for them if turned wide side up.
Remove top row of nests, or cover them up, the 4 lower nests are plenty for 9 birds.
Put an angled(45 degrees or steeper) board on top of nests so they can't land on it.
The feed can is tough....might put a hinged angled board attached to wall.
Maybe like what I did here for my waterer,
'hinges' are just a couple wires looped thru HC and holes in board,
hook above holds it up if needed: