SAS Version 9.0 was so foundational that subsequent releases (9.1, 9.2, 9.3, 9.4, and even M6 and M8 maintenance releases) built directly upon its architecture without a Version 10. In essence, the born in 2004 continues to serve customers today.
SAS 9 utilizes a multi-tier architecture to manage data and processing: Metadata Tier Sas Version 9.0