From Nikon Rumors and Nikon the shipping date is now December 24th rather than the 15th (with caveats...read notice as follows):

Notice regarding the release date of “Z 9” and related products and product delivery

December 08, 2021 Product information

Thank you for your continued patronage of Nikon products.

We are pleased to inform you that the release date of the full-size (Nikon FX format) mirrorless camera “Nikon Z 9”, which was announced to be released within 2021, has been decided on December 24th (Friday).

In addition, we have received a large number of reservations for “Z 9” and related products, which exceeds our expectations. For this reason, we may not be able to deliver the product to customers who have already made a reservation on the day of release. In addition, we are considering increasing production due to the favorable reception of orders, but due to the influence of semiconductor shortage etc., it may take time for products to be delivered even to customers who make reservations in the future.

We sincerely apologize for any inconvenience caused to customers who are waiting for this product.

We will do our utmost to deliver the product as soon as possible, and we appreciate your understanding.

Scheduled release date: Friday, December 24, 2021