Samsung China has started rolling Android 6.0 Marshmallow update for Galaxy A9 which is currently only available in China. The smartphone is the first A series mobile to receive Android 6.0 Marshmallow update.
SamMobile, has reported that the model number SM-A9000 handset should have a build number A900ZCU1BPE2 after the Marshmallow update! The latest update is missing AOD (Always On Display) feature, that allows users to enjoy goodies like Google Now on Tap and Doze features, these features is a part of Marshmallow update.
To grab this update head towards settings> phone updates and check for it. If you are unable to receive the update, wait for few hours or days as its an OTA update it will take time to reach to your mobile. Make sure that you have a Wifi connection to download this update with maximum charging in your phone while installing it!