AC continues to run for several minutes after shutting off
This is basically a safety feature.  In the case of heating, if the fan turned off immediately after turning off the thermostat, the heat buildup in the heat exchanger could cause it to eventually crack and leak carbon monoxide into your house, so the fan continues to blow until the heat exchanger sufficiently cools.  In the case of the A/C, there's no danger of carbon monoxide. But if the various coils in the A/C were allowed to heat too rapidly, that could also cause their premature failure, so the fan continues to blow air across them until they're within a few degrees of ambient.  If this were able to be disabled and you could find an HVAC tech to do so, I wouldn't hire him or her, nor the company for which they worked.