You're looking to download Cisco ASA 9.14.
The Cisco ASA 5500 Series has reached its end-of-sale and end-of-life (EOS/EOL) date. The recommended replacement is the Cisco Firepower NGFW (Next-Generation Firewall). cisco asa 9.14 download
However, I can guide you through the process: You're looking to download Cisco ASA 9
https://software.cisco.com/download/home/278875046/type/282462649 cisco asa 9.14 download
https://www.cisco.com/c/en/us/td/docs/security/asa/asa914/release/notes/asar914.html
Please note that you'll need to log in to your Cisco account to access the download.
Before downloading, you may want to review the release notes for ASA 9.14: