1. You need CA Workload Automation Agent for Databases (Database plugin) to run Database Stored Procedure (DBSP) jobs. You can use the Agent 11.4 and Database plugin to run DBSP_JOB job type.
2. Yes, you can install latest Database plugin on top of Agent 11.4 version.
3. The installer for the Database plugin is shipped with the Agent 11.4 ISO image. You can
download the Agent 11.4 ISO from CA Support website.