The Redmi 9 smartphone from Xiaomi has already started receiving MIUI 12 for users in China, but it seems that owners of the global variant will soon be enjoying the same software update. The GM of Xiaomi Indonesia has stated that MIUI 12 for the Redmi 9 should arrive in November if not before.
https://www.notebookcheck.net/Xiaomi-Redmi-9-should-get-MIUI-12-global-ROM-update-in-November-at-the-latest.496659.0.html
Well. The best upgrade of MIUI is when you wipe it all out and install LineageOS. Really, it feels like downloading more RAM. Not mentioning all those ~30 non-uninstallable non-freezable forced apps...