Even if they were to play the match, what would Bulgaria be playing for? Well… really, nothing. Bulgaria is practically out as the League C playoffs will be Georgia vs. Luxembourg and Greece vs. Kazakhstan, seeing where those four teams are in their qualifying groups and their chances of direct qualification. It will slightly impact whether two of Hungary, Serbia, or Montenegro qualify, however, as if Bulgaria were to forfeit the match, Hungary would officially confirm qualification, with Serbia waiting for the result of Montenegro vs. Lithuania (a draw there means Serbia also officially confirms qualification). Even if Montenegro were to win that match, Serbia would probably qualify anyway because they face Bulgaria in matchday 10, at home.

It’s practically guaranteed that Hungary and Serbia qualify while Montenegro will watch the tournament from home, seeing as they cannot qualify for the League B playoff; Bulgaria is guaranteed to be going home as there is nothing they will actually play for here.

To summarize briefly, cancelled or not, this match affects something, but ultimately affects nothing.