Also, if it was not referred to as "world war 2" during the actual war, when was that name agreed on?
It would appear that people were calling it "world war 2" from the outset.
The first large image on this page shows the front page of a newspaper from September 1939
http://www.archives.com/genealogy/newspapers-world-war-2.html
Russians called it the Great Patriotic War.