Brendan, isn't 9a simply a part of every 24d?
Personally I'm flummoxed by 18d, I have O_Y _ _ _ A _ for "Dweller on mountain, one seeking gold in 10, 24 down."
I can think of a 4-letter word O_Y _ which is something that lives on a mountain, but that doesn't seem to help me find the solution!
Where am I going wrong?