Not sure if you understand what Lucifer is. That is his proper biblical name and as one of god's few "perfect" creations the pious are remiss in calling him devil or satan.
Lucifer was an Angel. Rivaled only by few such as Michael and Raphael. He is perfect as all angels were created.
His crime was that he loved god above all others. You see, when god created man... he asked the angels to love humanity as they loved god.
To put it in perspective...
Put yourself in the shoes of an angel. Now, God asks you to love pigs as you love him.
Lucifer saw this as impossible. He didn't dislike humanity, he just couldn't reconcile worshiping them equal with the almighty.
As you are aware, God has big anger management problems. And for this act he cast Lucifer into the lake of fire. Along with 1/3 of the remaining angels... it apparently was a pretty popular opinion at the time.
The role of Lucifer has changed over the centuries. Now we have a Demon who is responsible for all evil and vice on Earth.
Which brings us to free will. You have it because God says you do. If that isn't irony....
One of the weirdest contradictions in the bible is free will vs. God's plan.
They are mutually exclusive yet must be harmonious. The big picture philosophy between these two forces are enough to make anyone's head spin.
But you are correct in a sense. According to the celestial story in christianity ... we are nothing more than a complex wagered game to our celestial overlords.
We are here... to prove a predetermined point.
I don't know how anyone could even wish for any of this to be true.
God cast Lucifer to the Earth.
Not until gentle Jesus meek and mild does the idea of eternal torment in hell fire come to us.