Can someone clarify when I backup Core Lightning with Start9 backup does that cover all my backup needs or is there something else I have to backup to recover channels in case of failure? Sorry if I missed this in the documentation but it was not clear to me after going through it.
The backup of the service will allow to to safely recover the service in the case of a disaster. The recovery process will close your channels, and send the funds back your on-chain wallet, minus the on-chain mining fees.