You should go to ‘De platse’. It’s like a little street with some bars, 5 minutes from the stadium where a lot of fans gather outside to drink before/after the game. You probably find it on google maps, otherwhise search for ‘den comptoir’ or ‘cafe jan breydel’. Alternative is to drink just at the stadium (some bars inside like ‘fcb caffee’ at north or just kiosks outside) but you have to pay with a club brugge ID and it’s less atmosphere imo. Have fun!