[awiouy]

@stasheck 
Your release of librespot is outdated.
Use the current revision (110) of the Librespot addon.

That'd explain it, but if it's available in repos, then I'm doing something wrong:
Kodi -> Addons -> My addons -> Addon repositories -> (context) Search for updates [done] -> back -> Services -> Librespot -> Update ===> I can only see 9.0.109.

What did I miss?

Nothing: the addons for LibreELEC 9.0 are outdated.