How to associate multiple symbols with one footprint in KiCad
Due to architectural limitations in Kicad, it is impossible to associate multiple symbols with one footprint. This is because the symbols carry the pin mapping information directly. In other CAD packages, there is a mapping layer in between that can remap the symbol pins to the footprint pins. In Kicad, what you have to do is make one symbol with two sub-symbols, one for each of the two amplifiers in the device, and with the appropriate pins assigned on each sub-symbol. Then, you need to make sure to instantiate both sub-symbols in the schematic for each IC.