First, verify if your manufacturer released an official update. Most devices from the KitKat era (circa 2013-2014) stopped receiving updates at Android 5.0 or 6.0. Go to Settings > System > Software update . Samsung: Check Settings > About device > Software update .
If no official update exists, the only way to reach Android 9.0 is through a like LineageOS or Pixel Experience. upgrade android 4.4.2 to 9.0
If no update appears, your manufacturer has likely ended official support for that hardware. 2. Unofficial Upgrade (Custom ROM) First, verify if your manufacturer released an official