If I purchase here, will I have the same access as the "Creator" subscription on Patreon? 

Will I need to enter some kind of code to access the creation of new scenes and some other things? Or is this only for patreon subscriptions?

Is there any differences  between patreon and itch io installer?

(I apologize if there are mistakes here, I don’t know English well)

If you purchase here you will have the same latest Virt-a-Mate 1.x Creator (currently 1.22) as you would get if you subscribed to MeshedVR on Patreon + vamX on Patreon. Plus it's a single installer that puts everything together in a much easier way then trying to build it from the two separate Patreons.  You don't even need to enter any code!