Where IS Satan?

So I had an interesting thought a couple of nights ago. Something that was completely new to me, and that caused me to think.
I have been thought my whole life that during the War In Heaven, Satan took 1/3 of God's children with him. Well, that 1/3 followed Satan based on their free-agency. These children, including Satan himself, would never have the capacity of receiving a body of their own.
So...where are they? Because they have fallen from the presence of God, right?
And can't you only have a world of your own, when you have lived a mortal life, and acquired knowledge? So why does Satan get to have a world of his own?
Then these things came into my mind:
A. Terrestrial State
Our world once was up with God, next to Kolob. When Adam and Eve partook of the Fruit, to gain knowledge and be able to return to God, our world fell into a Terrestrial State. But, through the atonement of Jesus Christ, and the resurrection, he will be able to return and bring this earth back to it's Celestial State. Perhaps, Satan's world has also fallen to a Terrestrial State, or even lower (Outer Darkness), but with no hope of ever returning back to a Celestial State. They don't have a Christ like we do.
B. Part of The Plan?
In God's plan, there has to be opposition in all things. Perhaps God knew in one way or another that Satan would leave with 1/3 of his children. Hence, Heavenly Father had a world prepared for Satan. The purpose of our earthly life is to make choices between good and evil, and Christ to save us from our sins.
C. Satan on this earth??
I mean, we are tempted by him aren't we? Or is it just a term we use for opposition in all things? Because to us, Satan represents all that is evil, and goes against the will of our Heavenly Father. I stated b efore that maybe his world is equal to our Terrestrial world. But what if it is not? What if it is Outer Darkness (what many believe). One who is in Outer Darkness can't "upgrade" himself to a higher State. A Terrestrial World is still much more aspired to than OD.
E. Satan as a poetic figure?
Isn't the Bible full of Jewish/ancient poetry? Why couldn't the term "Satan" or "Devil" just represent something to call something evil? But then again, Satan DID take 1/3 of the Hosts Of Heaven with him. And that isn’t made up.

Now I'm not saying I need to know the answers. Personally, I agree the most with option A. That was the first thing that came to my mind. The other ones were other arguments, that do make sence in some way.
But the time to find out isnt't right. I don't want to know the answers. It's just a thought that came up in me.