The A9 is more suited for silent shutter as it does indeed have a faster sensor read

Silent shutter is really only useful and dependable to me for street photography where I am typically well below 1/500th and under natural light

In this situation, silent shutter really shines and can lead to some wonderful candid photos

The other issue is using silent shutter under artificial light

I love the idea of a silent shutter

Without touch capture / shutter, I do not want to waste my money on a7riii nor a7iii