Hi mate
Last year I paddled my yak way up into Bells. I found a hole about 7 metres deep on a sharp U bend that had been cut into the bank. The bank was light coloured dirt/rock. Full of snags and looked very fishy. I marked fish on the DSI but didnt catch anything. I amagine you could get up there in a tinny at high tide but you may struggle at low tide because it gets very shallow prior to the hole.
Havent see one 9 metres deep up there and i have spent alot of time up there.