Is fiction considered to be a branch of creative writing?

Of course.  Fiction, not real.  So to be creative is to invent fiction,

Think of all the fiction that have become blockbusters in the movies - not real but invented by creative writers,  E.g. E.T., Lord of the Rings, Harry Potter.  These have proven so successful that many people believe them to be true - but they are fiction written creatively.

Yes! Probably the most creative form, as it per definition CREATES a fictitive something out of nothing that is per definition factual.

yes :) 

To create is to bring something that does not exist, into form. Fiction is something that does not exist. You create it in your head. Therefore whatever you create is fictional. It may be inspired by reality, but it's not real. It does not exist.

Not a branch - the correct term is form.  Fiction is one of the forms of creative writing.

You must create a fictional in your head taken from reality imaginable way that can be understood by everyone and that its transformation into a realistic read of certain imagine you are talking about himself or his neighbor or friend