My question is regarding the 40th aayat of Surah Tawba. I was talking to a Sunni brother online and we were discussing about the caliphs. He said that the first caliph’s martaba can be proved from the Qur’an and he put forth the 40th aayat of Surah Tawba as an example. I would like to know whether it is true that the aayats true meaning is in praise of the first caliph or not. Please clarify.

That is the verse of the cave.
No this verse shows God is supporting the prophet. Not necessary enough to prove that he deserves the caliphate.