welcome to the Polycom Community.
Have a look at the Setup & Maintenance Documents => here <= for the 9002, 9004 and 9006 as to my knowledge shows the 9002 is lacking the Audio input.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
The answer lies here
I stand corrected as the unit does have a shared Audio in as you correctly highlighted.
Thanks for following this up.