TVs with different suffixes are always labeled as different SKU for some reason. It can be different stand or screen bezel colors, curved vs straight stands, different preinstalled apps, different remote button assignments, lack or presence of a headphone jack, RCA or breakout cable analog input - these are just from LG OLED specifically.
In the case of C9AUA vs C9PUA, the PUA is certified as "WiSA-ready" for wireless speaker support and the AUA is not. This matters if you intend to connect recent model wireless speakers directly to the TV. Note that this connection still requires a separate dongle. I'm not sure if anyone has tested it with the AUA.
In the case of C9AUA vs C9PUA, the PUA is certified as "WiSA-ready" for wireless speaker support and the AUA is not. This matters if you intend to connect recent model wireless speakers directly to the TV. Note that this connection still requires a separate dongle. I'm not sure if anyone has tested it with the AUA.