God never called jack squat "planets". There is
Genesis 1:14
Then God said, "Let there be lights in the expanse of the heavens to separate the day from the night, and let them be for signs and for seasons and for days and years;
He did use the word "stars"
Psalm 8:3
"When I consider Your heavens, the work of Your fingers, The moon and the stars, which You have ordained;"
So forget this planet stuff. The sun and moon are lights, one for day and one for night. Yes they are round and appear flat since we see only one side.