1. 9III is using the latest AI chip that supports multiple subject recognition in photo/video mode, which more accurate subject detection 2. based on current test result (dpreview), the noise performance is roughly about < 1 stop worse than 9II. But in return, you are getting 120fps shooting speed
It is not as instant on like a high end DSLR, but it is very fast for a mirrorless camera specification. I did not miss out any spontaneous moments. Is is fast enough for me to response to a sudden photo opportunity.