I had no calm with this question either, mak a second try.
The context of this passage is:
The Jews said, “Ezra is the son of God,” and the Christians said,
“The Messiah is the son of God.” These are their statements, out of
their mouths. They emulate the statements of those who blasphemed
before. May God destroy them! How deluded they are! They have
taken their rabbis and their priests as lords instead of God, as well
as the Messiah son of Mary. Although they were commanded to worship
none but The One God. There is no god except He. Glory be to Him; High
above what they associate with Him.
The confusion is about the wow at the end 9:30:
وَقَالَتِ الْيَهُودُ عُزَيْرٌ ابْنُ اللّهِ وَقَالَتْ
النَّصَارَى الْمَسِيحُ ابْنُ اللّهِ ذَلِكَ قَوْلُهُم بِأَفْوَاهِهِمْ
يُضَاهِؤُونَ قَوْلَ الَّذِينَ كَفَرُواْ مِن قَبْلُ قَاتَلَهُمُ اللّهُ
Grammatically, this sentence can be translated as «God has destroyed them» or «May God destroy them», perhaps also «God used to destroy them».
The same formulation
قَاتَلَهُمُ اللّهُ أَنَّى يُؤْفَكُونَ
is also found in Quran 63:4 (referring to hypocrites). I first had a look onto various translations (not only English). They vary a lot;
9:30, 63:4 May Allah destroy them; how are they deluded?
9:30 May God assail them! How deceived they are!
63:4 God condemns them; how deluded they are!
9:30 May God destroy them! How far astray they have been led!
63:4 The curse of God be upon them! How they turn away!
9:30, 63:4 God do battle with them! How are they misguided!
9:30 Allah (Himself) fighteth against them. How perverse are they!
63:4 Allah confound them. How they are perverted!
Most translations follow Saheeh International, some put it into present positive (like Itani in 63:4, and Pickthall 9:30), once I found past tense (Pickthall 63:4).
«God fights against them» does not fit the grammar form.
«God has destroyed them» (I never found) does not fit well either because then they would not exist any more.
The translation of Pickthall would make sense in both criteria, but I think «confound» is quite an uncommon translation for قَاتَلَ.
Finally, I think, «May God destroy them» is correct. However, it should not be interpreted as a wish directed to God but rather like «Let God destroy them at the time. Give up to persuade them or to make them repent.»
It also fits well to the hypocrites in 63:4 as it is impossible to talk to someone about a problem that he denies. So let them see..
As to the context of 9:30, the Prophet was told that he cannot persuade the people had around him and to leave it to God to punish them.
(Remark: it needn't be impossible today; I already persuaded a Christian to pray to God, not to Jesus)