If it's Lefty's, save yourself the time. It's a tourist trap. There aren't any Bills bars in SF outside of the North Star. It's a short cab ride from where you're at to North Beach. I suggest you do that and watch the game amongst friends.
Might suggest you just eat at your hotel and the. Head to the game later. Nothing great in OP. Most places in Buffalo aren't open super early. A place like River Works or 716 might have brunch.