Currently there are 14 native Macro Prime lenses for Sony A9 III and 7 of these lenses are autofocus (AF) type.
A9 Mark III also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on A9 Mark III.
Since Sony A9 III has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 6 Macro Prime lenses with Weather Sealings.