This thread died a death but, having just downloaded official iOS 9 as a regular user, I came looking for the answer and found this thread.
Well done nj-Morris, you were correct. I only tried it towards the top of the right edge but you were absolutely right. Swipe from the right in the middle of the screen and it brings up the multi-tasking stuff, swipe in from the right towards the top of the right hand edge of the screen and it does the safari forward-page gesture. Thank goodness for that, even after an hour I was really missing being able to do the forward-page gesture.