I have been close to the location of your Sasquatch on BPB but no appropriate camera angles so could not see
Ahhh, well the Squatch is a hidden object, like the easter eggs and chambers signs. Unless you are at the precise location, you cannot see him. It is not about the camera angle, with these objects, it is the fact that you have to be right up on them for them appear, a yard or two off and you will never see him, or the eggs or the signs.
I play mobile sometimes, but never looked for stuff with mobile, only PC. I will have to try mobile and see if I can get the squatch. Looking for strange objects, and hidden stuff, is easier on a larger screen.
As for CB #9, I have been all over that place, looking for a sign. If you jump to the Chambers thread, there is talk about a trap door back where you are talking about. I wonder if what you are seeing is that door? Seems like an investigable.