Asav9-12-2-9.qcow2 Download [better] -
While there isn't a single "official" blog post dedicated solely to that specific version's download, the most reliable way to obtain and understand the image is through the GNS3 Marketplace and official Cisco documentation.
GNS3 provides a streamlined method via an appliance template: Asav9-12-2-9.qcow2 Download
After downloading:
This is the most popular use case. These platforms allow you to drag and drop the .qcow2 file to simulate complex enterprise networks without buying expensive hardware. While there isn't a single "official" blog post
Approximately 100MB to 512MB for the virtual disk. Asav9-12-2-9.qcow2 Download