John 9:35

The healed man had responded positively and courageously to the light that he had so far, but he did not have much light. Therefore Jesus took the initiative and sought him out with further revelation designed to bring him to full faith. When Jesus found him, He asked if he placed his trust in the Son of Man. Some early manuscripts and modern translations have "Son of God," but "Son of Man" has the better support. This personal response to God’s grace is essential for salvation. "You" is emphatic in the Greek text. Jesus probably chose this title for Himself because it expressed the fact that He was the Man who had come from God (Daniel 7:13-14; cf. John 1:51; John 3:13-14; John 5:27; John 6:27; John 6:53; John 6:62; John 8:28). Furthermore it connotes Jesus’ role as Judge, which He proceeded to explain (John 9:39).

Jesus was asking the man if he trusted in the God-man, though Jesus did not identify Himself as that Man. The blind man had never before seen Jesus so he did not know who He was.