The Jews say, "Ezra is the son of Allah "; and the Christians say, "The Messiah is the son of Allah ." That is their statement from their mouths; they imitate the saying of those who disbelieved [before them]. May Allah destroy them; how are they deluded? (Surat At-Tawbah 9/30)
They have taken their scholars and monks as lords besides Allah , and [also] the Messiah, the son of Mary. And they were not commanded except to worship one God; there is no deity except Him. Exalted is He above whatever they associate with Him. (Surat At-Tawbah 9/31)
From these verses, we can understand that at least some Jews claimed such thing. But this doesn't make them out of the People of Scripture. The People of Scripture is a term used for Christians and Jews. Their wrong believes or actions don't change this.
Neither those who disbelieve from the People of the Scripture nor the polytheists wish that any good should be sent down to you from your Lord. But Allah selects for His mercy whom He wills, and Allah is the possessor of great bounty. (Surat Al-Baqarah 2/105)
As you can see here, there may be disbelievers inside the People of the Scripture.
O People of the Scripture, why do you argue about Abraham while the Torah and the Gospel were not revealed until after him? Then will you not reason? (Surat 'Āli `Imrān 3/65)
In this verse, you can see the People of the Scripture is a sum of Christians and Jews.
In the verse you gave, it is not said "they worship only to Allah", rather it is an invitation "to worship only to Allah". Otherwise, it would contradict with the verses I gave, especially with "Surat At-Tawbah 9/30" and "9/31".