[User 224999]

Is there a way to prevent this addon from caching?

Or to limit the cache size to a very small value? Used with default settings I'm seeing close ~350MB of use (and I use it rarely), of content that I don't need cached. For a small RPi running off of an SDCard this is not needed.

Also is the cache (.kodi/userdata/addon_data/plugin.audio.spotify/libspotify/cache/Storage)
safe to delete without breaking the addon? (it would be nice to have UI for this)

Caching is required by Spotify and maintained by libspotify itself.
No worries, it won't drain your disk, it's only a limited amount of space taken.

You can safely delete the cache files but that's kind of useless.