[eusi]

Running the update at a specific time is not possible at the moment.
Running it via Cron would require the possibility to run this Kodi addon directly from the shell, which could be possibly by the tools from kodi-eventclients-kodi-send (command kodi-send).
I added this to the github issue tracker, but probably I will not find time to implement this via the addon settings.

@schapplm, Thanks for the reply!
Maybe you can get inspired by the source code of Library Auto Update, which uses this cron mechanism already.