[Formendacil]

Yes.

Completely, definitely, and totally.

The Legendarium, from the Ainulindale down to the fall of Sauron was intended to be the history of this world, in a somewhat distant time B.C. This same world which, in Tolkien's faith, is under the dominion of God. Therefore, if the world in that time was under the dominion of Eru, then Eru must be God.

Eru and God are intended to be one and the same.

And I personally feel that no amount of "personal opinion" on the matter changes it. If you accept the existence of Frodo, Sam, and Gollum in Middle-Earth, you have to accept the existence of Eru- as the Judeo-Christian God within the story.

Do as you wish in real life, but within the confines of the story you have to, in my opinion, accept Eru, as presented, as God, if you are going to accept it at all.