Just wanted to share the following and hopefully it will help others.
When my KM8P+ got upgraded to the CE 9.0.3 version with kodi 18, I noticed the was a notification (Processing … 0% – with a spinning wheel) on the upper right-hand corner that lasts for 3+ minutes every time when the device boots to its main page (Weather). Also, trying to watch any YouTube stream was almost impossible, i.e. hit-or-miss, etc., with a spinning wheel in the middle of the screen after clicking any YouTube feeds. Anyway, I finally resolved this issue, i.e. no more notification and no more problems with YouTube feeds, by doing some media library maintenance (Kodi -> Settings -> Media -> Library -> Clean Library). This process was very slow which took a couple of hours to complete and only consumed no more than 5% CPU resources. BTW, this is NOT a CE but rather a kodi issue. It also happened to my Kodi 18 on a Ubuntu Linux Desktop computer and the fix is similar.