How do you get a Cisco VPN connection to remember its password?
I guess you are using anyconnect to connect to the Cisco VPN server. AnyConnect can also be used from Terminal. This works on macOS Sierra and AnyConnect 3.1.14018. Create a bash script with the following command:

/opt/cisco/anyconnect/bin/vpn connect your-vpn.server.here -s &lt;.credentials


And put the login details in the file .credentials with the following three lines:

0
your-username
your-password


Don't forget to put reasonable permissions on the files.