These words spake his parents, because they feared the Jews: for the Jews had agreed already, that if any man did confess that he was Christ, he should be put out of the synagogue. Put out of the synagogue - That is, excommunicated - separated from all religious connection with those who worshipped God. This was the lesser kind of excommunication among the Jews and was termed nidui. The cherem, or anathema, was not used against the followers of Christ till after the resurrection.
Related Commentaries of John 9:22
John 9:22
22 These words spake his parents, because they feared the Jews: for the Jews had agreed already, that if any man did confess that he was Christ, he should be put out of the synagogue.