For the shrink wrap it depends, if the fit isn't great across the forefoot / arch then it should be wrapped also.
A 1/2 size too big is a 1/2 size too big, it doesn't go away. Yes, you can remold the boot and squeeze / wrap / clamp the sides in but then they only stay there if your mechanics are good. If your mechanics aren't good then the boot is going to expand out again quickly. Don't be fobbed off with a rebake, if you believe they are made a 1/2 size too big (this happens all the time) you should be asking for a remake. These are customs skates built to fit your foot and you are paying for this.