No. He probably meant that Jesus is the God of this Earth, which is very different from the world. The world is the man-made civilization and governmental structures and boundaries that exist because of it. The Earth is the full existence of this planet and all life on it.

Satan is the god of the world, for the world believes and follows his doctrine. Jesus is the God of this Earth, for all nature believes and follows his doctrine.

However, if you were trying to claim the trinity I am not surprised he disagreed. Now, Jesus is God, in that he holds that title as a member of the Godhead. He is not, however, God the Father, and is most frequently distinguished from our grand Head by the Title Lord Jesus Christ. While they are both God, in that both share that Title being members of the Godhead (as does the Holy Ghost) they are still very separate and distinct beings. As such, to say that the trinity is wrong is correct.

Which took me aback because I knew that is how Satan is described in the Bible, as “the god of this world”.

You are probably going to tell me, “He meant to say that He (Jesus) is the God “over” this world, not “of” this world…

And while I see that you can see the trinity, I do not think this was the intent of Isaiah, and I can also see the LDS doctrine of God.

A title is an additional name given to a person to distinguish them from others. I am now reminded of the play “Man of La Mancha.” At one point he is being knighted, and he says “If your Lordship recalls, it is the custom to grant the new knight an additional name.” In response the one performing the ceremony gave him the name “Knight of the Woeful Countenance.” This is very much a title or description of who he was, but it was given as a name to distinguish him from others.

In the same way all these descriptions that are given by Isaiah are Titles, or additional names describing Christ, given to distinguish him from others.

Do you see the Trinity in there?