“They say unto the blind man again, What sayest thou of him, that he hath opened thine eyes? He said, He is a prophet.”
They say unto the blind man again, What sayest thou of him, for that he hath opened thine eyes? And he said, He is a prophet — the Pharisees turn back to the healed man, asking his judgment of Jesus ('What sayest thou of him?'). The man's answer has developed: 'He is a prophet' (prophētēs). This is an advance from his initial identification ('a man called Jesus'); he now recognizes prophetic authority and function. A prophet, in Jewish thought, speaks for God and performs works of God. Yet the title 'prophet' falls short of the full truth (Jesus is more than prophet), and the Pharisees will press him to further positions.
Church Fathers on John 9:17
The neighbors therefore, and they which had seen him that he was blind, said, Is not this he that sat and begged? Wonderful clemency and condescension of God! Even the beggars He heals with so great considerateness: thus stopping the mouths of the Jews; in that He made not the great, illustrious, and noble, but the poorest and meanest, the objects of His providence. Indeed He had come for the salvation of all. Some said, This is he. The blind man having been clearly…
His eyes being opened had altered his look. But he said, I am he. He spoke gratefully; a denial would have convicted Him of ingratitude.
Thus he represents the state of the catechumen, who believes in Jesus, but does not, strictly speaking, know Him, not being yet washed. It fell to the Pharisees to confirm or deny the miracle.