I would like to film a specific Sim getting thrown out of an alien spaceship, is that possible to somehow set up? Is there maybe a mod for activating cut scenes? Or how do I ensure the sim gets abducted by aliens?

Get your sim abducted by aliens, you can do this one of two ways:
Basegame: Open up the cheat window and type in "Boolprop testingcheatsenabled true", shift click on a telescope and click "get abducted"
Or
Freetime: Use the aspiration benefit "summon aliens" - a knowledge adult sim fresh out of CAS should have enough points already to unlock it.

I can't remember how long Sims are abducted for, but when they return they'll do the cut scene animation (check in the options menu to make sure you have cut scenes enabled). Just make sure to click "v" or set up an external programme before they return

Thank you friend!

If you mean how to turn them on ingame, there's a button in the ingame "camera options" called "Special event camera" that needs to be enabled for the cutscenes to work. If it's deactivated you don't get the scenes.

Sometimes the event camera can get at least partially blocked by other sims walking past, walls, furniture, etc., so make sure there's plenty of space around the telescope, and nothing that's blocking the view.

Notes taken!

There is also a telescope you can download from here that will get your Sim abducted every time they use it. I have used that for story purposes before.

awesome, thanks!