Clarification regarding 9 Box rating process

Summary:

As per the out-of-box functionalities, 9-box ratings are directly sourced from the talent review page. Additionally, most organizations conduct talent reviews for a critical mass. My current client use 9-box ratings for their entire workforce. I believe conducting a talent review process for the entire workforce could be a daunting task.

I am interested in knowing if we can populate 9-box ratings outside of the talent review process, possibly through HDL or a spreadsheet loader.

Has anyone implemented a process to complete the review of 9-box ratings for a large population outside the standard talent review process? What would be that process looks like.Your advice would be greatly appreciated.