ArcGIS Desktop (ArcMap) version 10.8.1 is the last version for this GIS software that we have been using for many years. There will not be a 10.9 version. You are encouraged by ESRI to move on to ArcGIS Pro.
ArcMap 10.8.1 will be supported until March 1, 2026. Most of you probably knew this already, but just in case click here for more info.