Capturing territories during the war (Stellaris)

Is there a way to capture another empire system with inhabited planets inside without landing armies on these planets?
I remember that there used to be some kind of megadeways-destroyer of planets, but I don't know if he's in the game now.
The problem here is that I have a company for an aggressive all-consuming mind hive, and manual management of hundreds of inhabited planets (switching automation somehow do not affect anything) very much tires and takes even more time than anything else that could be engaged in the game.