The more I look at the high resolution image that Nikon released to the press (see below), the more I believe the asterisk. In case you don't recall, the asterisk was "The appearance of the camera may differ from the photo shown above."
The things that strike me as odd about the image are these: (1) it's Z, not Z9; (2) the red swoop looks like a decal; (3) the two button reset and two button format shortcuts are stenciled on the body, with the two button reset returning to the exposure compensation button; (4) the 10-pin and PC sync connectors are angled outwards; (5) there's no snap line for the plastic part that would house SnapBridge components; (6) we've gone back from the small red self-timer indicator light to a big autofocus assist type light on the front (and on the opposite side); (7) the Focus Mode button is also angled and does not seem to have a switch around it; and (8) there are no microphone holes visible.
Now it very well may be that yes, the Z9 is different from the D6 body design in all those ways. It may be that only some of those things are true for the final Z9 and that the photo is touched up from a late prototype. Heck, it could be that someone at Nikon photoshopped a bunch of existing parts together to approximate what the final camera looks like.
I'm thinking that you shouldn't doubt the asterisk. Thus, all the masterful measured mockups popping up around the net probably aren't going to tell you the exact size of the final camera.
