It appears that AirWave 8.2.9.0 enables stronger SSH ciphers.
Specifically:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr
MACs hmac-sha1,hmac-sha2-256,hmac-sha2-512
KexAlgorithms diffie-hellman-group14-sha1,ecdh-sha2-nistp256,ecdh-sha2-nistp384
AOS 8.2.1.1 (Aruba Activate's default image as of June 2019) does not support any of these ciphers.
The config will backup with proper SNMP configuration, but the flashbackup which uses SCP will fail.
Aruba TAC does not have an answer yet as to what the highest level of SSH cipher 8.2.1.1 will support to be able to add to AirWave /etc/ssh/sshd_config just yet.
So if you're flashbackups, and SCP firmware upgrades are failing after upgrading to 8.2.9.0 you'll likely need to downgrade the SSH cipher suites in use.
For those using FTP to upgrade we are also running into issues with the ncftpget process on the controllers and receiving a
"could not accept data socket." error, switching over to SCP resolved the issue.