I am trying to understand this statement in the light of an earlier statement that Jesus made to Nicodemus. He has said that the Son came into the world NOT to condemn it, but to save it (John 3:17). How does that square with this statement? I believe the answer is found in the audience of each statement.
In John 3, Jesus is dealing with an inquisitive seeker who has come to Him to find questions answered about eternal life. And the salvific purposes of God for the world flow from that conversation. The world has the potential for salvation by Jesus. Generally, God’s grace is offered freely to the entire world. But some will receive it while many will reject Jesus.
The John 9 conversation (at least at the end of the chapter) is directed to those who have see Jesus testify to His deity. They have seen a man born blind testify to His deity. They have seen a man born blind testify to Jesus’ work and power. And they continued in blind unbelief because to change would destroy their incorrect theology. That is why judgment would come. They refused to accept their sinful beliefs. Even in this statement, Jesus makes it clear that blind people (those lost and spiritually dead who believed Him) would see, and those who thought they saw (spiritually self-righteous who refuse to repent) would be blinded by Him. That is the difference between John 3 and John 9.