Yes, you can turn off the AC breaker. If you do not know what to do with your faulty AC circuit breaker, it would be best for you to switch it off pending the time you can have a technician come around to check it. Once the breaker is shit off, all your components like the compressor, the evaporator, and some other components will be shut off as well, which means you will be reducing the chances of getting those components damaged.