I read about half this thread. Not sure if I'm covering new ground, but here goes:
This camera will revolutionize many industries. As soon as I read the announcement a few weeks ago I knew Sony was going to win big with this one. Only if there's a technical glitch will this thing fail. Here's why:
* The film and television industry is going to drop everything for this machine. I'm talking about unit still photographers. There's one on every single TV show and film. They are ghosts on the set. Barely seen, and NEVER heard. The evolution/revolution is already taking hold because of mirrorless, and the A9 was already invented in the minds of each unit still photographer. They used to use big DSLRs with unwieldy, heavy sound blimps. Imagine going from that to a compact A9. Heaven. The sound blimps were a grand, not counting each tube that you needed for each lens. Many settings had to be configured ahead of time with the lid open and, yada yada: sound blimps are annoying, but were a necessity.
* The Sony A7s was the first step for unit still photographers. Finally a full-frame camera that was 100% quiet. Sure, iphones are quiet, and many point and shoots, but the biggest obstacle on set is light. The photographer never gets to choose the light, so flash is out of the question (remember, they have to be ghosts). The A7s and A7sII had a silent shutter mode that didn't cause distortion. So, problems solved, right? Well....not exactly. The A7s and A7sII were fantastic in low light and were 100% silent, but they were only 12mp of resolution. So making billboards is more of a challenge, and 12mp doesn't give much room to crop. Better get a lot of telephoto primes or hope your zoom can nail the shot.
(Side note: Grabbing a still from video can't compete with the quality of a still from a dslr/mirrorless, and the stills need to be perfect for the movie posters, magazine ads, etc.).
* A couple facebook friends of mine shoot as unit still photographers. They immediately dumped their Canikon gear for the Sony A7s series. Interestingly, though, one of my friends recently jumped into the Fuji system as well: Fuji X-T2. Why? Silence AND higher resolution (24mp). It works in many situations, and when it gets dark the Sonys take over.
* And that brings us to the A9. Is it full frame? Yes. Does it shoot a boatload of photos per second? Yes. It it higher resolution? Sure is. Is it silent? 100%.
It will become the number one stills camera in the industry before the end of the year. I guarantee it.
And, if the members of the various pres corps are wise, they will get one as well before they are made to. Listen to a Whitehouse press conference (or any press conference for politics, sports, etc.). It sounds like a classroom of kids playing with bubble wrap. That needs to stop.
I don't believe this thing will make much of a difference in sports (with a couple exceptions--golf, tennis, gymnastics and more), but in Hollywood it will own the day.
I want one. Can't afford one, but it would be nice.