Minimum wins to qualify for playoffs

Total number of matches to be played = 9C2 *2 = 9!/(2!7!)*2 = 8*9= 72 and each team will play 16 matches.

Case 1: Lets say if Team A and B and C wins 14 matches each(they will loose 1 game each from other two teams), then team D can win only 16 – 3*2 = 10 matches.

Case 2: Lets take a case where Top 4 team wins 13 games each

Team A: wins 13 matches, looses 3 games from B,C and D
Team B: wins 13 matches, looses 3 games from A,C and D
Team C: wins 13 matches, looses 3 games from A,B and D
Team D wins 13 matches, looses 3 games from A, B and C

Now Team E, can only win maximum of 8 matches as it A,B,C and D will win all matches played by E.

Case 3: Lets say top 5 teams wins 12 matches each

Team A: wins 12 matches, looses 3 games from B, C, D and E
Team B: wins 12 matches, looses 3 games from A, C, D and E
Team C: wins 12 matches, looses 3 games from A, B, D and E
Team D wins 12 matches, looses 3 games from A, B , C and E
Team E wins 12 matches, looses 4 games from A, B, C and D

In this case, team E though wins 12 matches but still don’t qualify for playoffs(assuming lowest run rate).
Thus from case 2 we can say that a team has to win at least 13 matches to ensure a place in playoffs.