Based on the instructions provided, it seems that the new bearing needs to be installed on the backrest's shaft journal. However, it's unclear whether the link arm bushing, link arm, and link arm support are necessary for the installation of the rear armrest. It's best to contact Volvo directly or reach out to a Volvo dealership. They will have access to accurate information regarding the specific parts required for the installation of the rear armrest in your 2009 C30 R-Design.