There were a lot of changes between 9.2 and 10 (completely new graphics stack on RPi, python 2->3 change etc) so it was a gamble if upgrading worked or not - hence our decision to not officially support it. LE10->11 should be a lot smoother (still there might be issues with addons, they have always been the main obstacles).
Migrating just your movies/music collection isn't too hard (search the forum, there have been detailed discussions about it).
Basically stop kodi (systemctl stop kodi), delete all MyVideos and MyMusic databases in .kodi/userdata/Database, copy the latest versions from your old installation there and also restore .kodi/userdata/sources.xml, then reboot (or start kodi again).
so long,
Hias