The AI would need to lead the target under any reasonable implementation. Just clicking the mouse when crosshairs are over a target would scarcely deserve the name AI.
Leading the targets makes this MUCH harder from just an over the counter object detection AI. In fact making that and making it look human so it's not trivially detectable would blow this from a weekend project you can do in a few hours(Which I already doubt.) To weeks/months/years long project since you need it be really humanlike... Even now cutting edge AI can be spotted by humans.