I read from ‘A History of the Jews of Arabia: From Ancient Times to Their Eclipse Under Islam’ by Gordon Darnell Newby, pages 59-61.
Qur’an 9:30: The Jews say: “Ezra (‘Uzair) is Allah’s son,” and the Christians say: “The Messiah is the son of Allah.” These are merely verbal assertions in imitation of the sayings of those unbelievers who preceded them. May Allah ruin them. How do they turn away from the Truth?
So when the Quran says, the Jews say Uzair is the son of God, it’s saying they worship Metatron. The Quran obviously does not approve. And some Jews didn’t either – Jews called the Karaites dismissed Rabbinical Judaism as polytheistic because of this Metatron idea.
So the Quran’s polemic is directed against a medieval Jewish aberration rather than what you might find taught in an orthodox Jewish synagogue today. The Qur’an is NOT criticising Judaism as such but taking the Jewish Karaite view over against the Rabbinate view.