How are conferences going to determine the winner of a division when one team has several canceled games, finishing, let's say, 6-0 in league play, while another goes 7-1? Or 9-1 vs. 8-0?

Winning percentage seems like the best solution there. You could also simply go with number of wins.

This happened with the 2007 MAC.

Miami 5-2
BG 6-2

Miami played for the title as they beat BG H2H.

Because no one is playing a 13th game, every conference can develop their own criteria for determining a “champion”. The NCAA only restricts the rules for conference championship game participants when teams are playing a 13th game. This could be an interesting twist because there are a significant number of games being cancelled or “postponed”.

The ACC has already announced their policy:

1) Its based on winning %, not total wins, but with the following caveats:

a) To be eligible to be considered for the CCG, a team has to have played within one whole game of the average number of conference games played. So for example, if a team only played 7 conference games and the average is 9, then they are ineligible for the CCG even if they are 7-0 and two other teams are both 7-2. You would have to have played 8 conference games to be eligible for the CCG.

b) Also, if two teams are tied in the loss column and are both eligible under (a), then H2H trumps winning %. So for example, if the conference average # of games played is 9, and team A is 8-1 while team B is 7-1, but team B beat team A, then team B would go instead of team A despite A having the higher win %. But if team B is 6-1 and beat A, then A goes because B does not qualify under (a).

2) After that, if teams are still tied, or if there are 3-way ties, then other procedures apply. See here:

https://theacc.com/sports/2020/9/23/FB_0923200510.aspx