What do you mean by a "backup instance"?
If your ASA 5585-X is part of an HA pair, then you would manage both FirePOWER modules in FirePOWER Management Center. Group them together and any policies you apply will be synchronized to both modules.
If the ASA 5585-X is stand alone, there is no backup instance. In the event of failure of the SSP, you would need to bootstrap any replacement unit and then reapply policies from the managing FMC once you have registered the replacement module.