All endings including invalid ending, correct?

Yes

1 more thing, for all endings. Do i have to let the endings play out? or could i exit out?

You have to have reached the end requirement for each of the endings (in that category), so e.g. for Invalid ending you must have the 'GAME OVER' screen show up before you exit the game, just like in the Invalid ending category

so the credits don't count for like good ending and genocide

Yeah they don't count