Part of the fun playing in a competitive 9-ball league like yours, is when your B steps up and beats their AA.
It's a good way for B players to play great players without any risk.
In BCA 3-man 9-ball of course there is a team handicap, but the player still has to win and get points, and the handicap isn't that big of a deal on most nights.
The better teams still win, the weaker teams win every once and a while, and everybody plays everybody.
Back to the warm-up, I would try to get there early and just work on long hard shots, getting the cueball around the table, draw shots, etc, don't get into a game.