I did and helped out on 5 downgrades. Each time the system was upgraded to 10.3 prior. The downgrade worked in each case, without any soft-bricks or failed mid-downgrades, etc. The key seems to be to eliminate issues from downgrading from any version < 10.3. Seems the best and most tested case is downgrade from 10.3. Because the most current version is 10.5, you really don't have the option of "trying" the downgrade from < 10.3, incase it fails. If it fails and you soft brick, you upgrade to 10.5 and game-over.
Your best bet is to sysupdate to 10.3 then downgrade to 9.2.