There is no real refrences I've been able to find to Tolkien's work during the Second World War. He was an exprt on Norse and Eiropean sagas, as a lot of German code words refered to this stories, I've been told he was attached to Bletchley Park to advise on what such codenames might reveal. During the Great War he was a signals officer in the 11th Lancashire Fusiliers, arriving in France 6 June 1916, he did see front line action but was invalided home with fever and never returned to the front. I did a Level 3 Communications project on the Great War a few years back, part of the project was a presentation on J.R.R. Tolkien and the influence of his Great War service on Lord of the Rings.
Both Lewis and Tolkien were commited Christians, compared to the Narnia books, Tolkien's lack of any religious trend in his books was wondered about at the time.