From Marantz’s website:
"I cannot upgrade my SR7009 with Auro 3D. What can I do to get the upgrade?
Due to a technical modification for the AV receiver SR7009, it is currently not possible to upgrade some units of SR7009 with Auro 3D.
You can identify these units by having a 3 at the 9th digit of the serial number (xxxxxxxx3xxxxx) which can be found on the back of your receiver or on the carton box. There is no upgrade ID displayed in the menu of these units when searching for new features. If you have such a SR7009 and would like to upgrade to Auro, contact the customer support team for further information. Please include the serial number of your unit in the mail."
Some may get lucky, some may not