Welcome to the challenge of hunting treeless. My first advice would have been to have your blind up by at least Sept. 1, preferably earlier. I build permanant box stands at my place. They stay in place all the time and the deer get used to them. Pop ups need to be in place a while so the deer find them not to be a threat. I'd say the deer were blowing at the change in their environment, not because they knew you were in that new brushpile that appeared recently. Give it sometime and they will act like the little buck did.

Can't give you any advice on seeing your pins. My scope on my crossbow gathers light which is a big help that last few minutes of daylight.