Versions 8 and 9 were skipped for the purposes of aligning the FTD and ASA software versions. Unfortunately, this did not happen with this release and ASA is still on 9.x but that will hopefully change next CY with the next major/minor release where we will see both ASA and FTD software versions on 10.x
About your 2nd question: Adopting a brand new release should only happen if there it introduces a critical feature that is needed in your environment. Otherwise, the current suggested (Gold Starred) version is the way to go.
Thank you for rating helpful posts!
Thank you for rating helpful posts!