As I said, if God created life on earth, why would he stop at just one planet. If you were growing flowers in your garden, you would not stop at just one seed.
I will therefore argue that if God created life, he created it everywhere. He created it on all the habitable planets in the universe. Therefore, my argument that we are not alone stands, even in a biblical sense.
There is no if in this - our eternal life, life after death on earth, depends on this belief.