I've got 2 remotes. Since 9.0.0 they don't work anymore.
See picture. The left one (no brand) always had minor problems: cursor mode always automatically switched to mouse mode, so before I did anything most of the time I had to switch to cursor mode, which I find nicer to use. It was usable that way. The right one, a Rii mini N7, never had problems at all. Both remotes use a wireless dongle on my Raspberry Pi 3.
Now, with LibreELEC 9.0.0 bot remotes are rendered useless. The left one (no brand) scrolls and scrolls, no matter which mode it is in. The right one cannot choose menu options like the gear icon for settings.