Is this hack? Will I be banned for using it?
Klikator-Garena only simulates mouse click so there's no way it could be identified as hack.
Only hack used is (optional) "Remove 5 sec wait", and it doesn't change Garena files, only memory location.
Does this work on 64-bit (x64) systems?
Do I need to turn off Game List when game started?
No, notifications are disabled by default while Warcraft 3 is focused (can be changed in Settings).