Despite letting Tesla chat know I wanted to delay delivery, looks like the message wasn't received at our local SC and I got a text/call that the car was at the lot early and could be picked up on Sep 8th - one week early.
Talked to the local advisor and was up front about wanting to wait until Battery Day cause I'd hate the feeling knowing there was a potential announcement of a change that could be worth waiting for and I didn't wait and took delivery of a car I don't need today any more than a month from now - he said he completely understands, doesn't think they'd really announce any change to the Y so soon, 'but you never know, so I get it'.
So I'm now officially delinked from the VIN and I may end up getting assigned a new one right away and it may also end up being routed/setup for delivery before Sep. 22nd but if that's the case, can unlink that one and do it again until I have the information I need on battery day to decide when to take delivery.
Super easy process all around and I am so much more at peace without the anxiety of 'what if I'd waited' - now I can wait and maybe nothing changes after all for the Y, and even if it doesn't, great - I'll get an awesome car and I can't wait....well maybe I can, a little.