Here are some of top options for Sony a9 III:

1. Sony HVL-F60RM2
- Official Sony flash designed to integrate seamlessly with the A9 III
- Guide number of 60m at ISO 100
- Wireless radio control for off-camera use
- Quick, quiet recycling and stable continuous performance
- Ideal if you want maximum compatibility and performance

2. Godox V1 Pro
- Round head design for natural catchlights and even illumination
- Powerful guide number of 60m at ISO 100
- Wireless 2.4GHz radio transmission with TTL auto exposure
- More affordable than the Sony while delivering great performance
- Good option if you want great bang for your buck

3.Profoto A10
- Premium compact studio light with AirTTL support for Sony
- Round head with soft, gradual light falloff
- Powerful with 76Ws output despite small size
- Fastest full power recycling of 1 second
- Go with this if you want top-tier pro flash performance and quality

Besides on-camera flash, you may also try some off-camera flash, such as new released AD600PRO II from Godox.

If u need a high-end studio light, the best choice is Profit A10.

Profoto A10 or Sony HVL-F60RM2

No way, I literally just dealt with this yesterday. Small world.

My buddy told me the exact same thing last week. Guess he was right lol.

Godox V1Pro S is a budget and professional flash for Sony a9 III.

For versatility, I'd suggest the Godox AD200Pro. While it's not a traditional on-camera flash, it can be used both on and off-camera. It provides much more power than a typical speedlight, which can be really useful for outdoor portraits or when you need to overpower the sun.

What is your budget ? If you don't concern about price, the ProFoto A10 is the best choice.

Godox V1 Pro.

Sony HVL-F60RM2