It says "circle", not "sphere".

The Bible is not a scientific source and doesn't affirm or disaffirm physics.
No; it says “khug” in Hebrew, which can be translated “sphere”. (The same word is translated “vault” in Job 22:14, indicating three dimensions; this is in the NLT, ESV, NASB, and others.)
There would be no way to circumnavigate a disk-shaped planet. There would also be no curvature from pole to pole.
The Bible is more scientific than a lot of our so-called “science”, which according to the scientific method must be based on observation first, and observation plus the Hebrew original of the Bible indicate the sphere.