He didn't call her Captain Marvel, he said she is called "Miss Marvel" in the script. Also, Danvers took up the title of Captain Marvel in the current Marvel NOW comics.
And on top of Mayimbe and Faraci, Drew McWeeny also believes there's a very good chance Miss Marvel will be in Avengers 2, and he's the most trustworthy of them all. So yeah, seems like a foregone conclusion that Danvers will be in the movie with 3 well connected people saying people have told them she is.
Just when I thought I can't get anyone excited for this movie!