score:4
No, there will be no extra buses or train to return to Brussels. I wouldn't even make sense because the combi-regeling will be in effect. This means that all Anderlecht supporters must book there tickets through one of the official fan clubs and they must come with the bus of the fan club. They can not even enter the stadium if they would drive themselves. The people that return to Brussels after the match will invariably be Anderlecht supporters that will be on their charter bus and not on any public transportation.
So you have two options: