Young Lion, Christ said that to the Pharisees, not the blind man.
 And Jesus said, For judgment I am come into this world, that they which see not might see; and that they which see might be made blind.
 And some of the Pharisees which were with him heard these words, and said unto him, Are we blind also?
 Jesus said unto them, If ye were blind, ye should have no sin: but now ye say, We see; therefore your sin remaineth.
This scripture below will help the I Iverstand it.
 If I had not come and spoken unto them, they had not had sin: but now they have no cloke for their sin.
 He that hateth me hateth my Father also.
 If I had not done among them the works which none other man did, they had not had sin: but now have they both seen and hated both me and my Father.
 But this cometh to pass, that the word might be fulfilled that is written in their law, They hated me without a cause.
In John 9:41, Christ was showing the Pharisees that they no longer can claim to not know they have sinned, because Christ removed the cloke by speaking the words he spoke and showing the example he showed. There is no more excuse because they have seen and heard what Righteousness is, and have heard what wickedness is.
I think what He means when he says in John 9:39 "and that they which see might be made blind." is that for those that already see what sin is and have chosen Righteousness, that he will remove all temptation by Rising the Irits of God within them, so that they will no longer have to resist temptation because temptation will not be able to approach them.