“As far as God creating light before He created a sun. We get out physical light from the Sun but God does not need the Sun to provide light.” The sun’s function of producing light is secondary.
“God is all powerful and is perfectly capable of creating anything He wants to all by Himself, without the Sun.” Without the relative mass and rotation of the sun, earth, moon, and orbiting planets, life wouldn’t exist on earth. To think that the sun was created on the fourth day is ridiculous.
As far as the “waters above the Earth”,
That’s not a correct rendering. I will provide the full translation, “And God said, “Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.” 7 And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament; and it was so. 8 And God called the firmament “Heaven.” And there was evening and there was morning, the second day.”
The firmament here in reference to is the expanse of space directly above the earth, and not outer-space, as some assert. It divided the waters from waters, which is to say, it divided the super-incumbent vapors which were above the abyss of waters below. The waters above the firmament are the vapors resolved from the waters which are raised above a part of the atmosphere, and from which the rain falls. The net result was the clearing of the atmosphere. Furthermore, the firmament is called Heaven for the sole reason that the space it occupies divides between certain water vapors, and those waters which flow more fully on earth. (De Gen. ad Lit., II, iv. 7)
However, with that being said, there is more to the text than I have mentioned, which I won’t include here.