There is a variant among the manuscripts in Deuteronomy 32:8. The Masoretic text has the “sons of Israel.,” whereas the Dead Sea Scrolls and the Septuagint have “sons of God.” There is no important biblical doctrine at stake in this question. However, it is likely that a well-meaning but unwise copyist made a change in Deuteronomy which ended up in the later Masoretic text. Let me express my opinion. A general rule of lower criticism is that the more “difficult” reading is likely to be the correct one. On this basis, I would call the “sons of God” the more difficult reading. It is a logical and reasonable interpretation of the DSS and Septuagint to have Deuteronomy 32:8 be describing how God divided the Promised Land into 12 territories for the tribes of Israel. Therefore, it would not be a huge shock if some well-meaning but unwise scribe changed “sons of God” to “sons of Israel” for the sake of clarity (not because of possible polytheistic implications as you imply). Based on this, it is my opinion that the DSS is the original, and the Septuagint is a literal translation from the original.
I am aware of the idea that God assigns specific angels to specific nations. The idea is found in Daniel, as I assume you know. However, I see no reason to apply Deuteronomy 32 to this idea. Most likely, these “sons of God” are the people of Israel. Is it possible it is about angels? I suppose so, but not very likely. Either way, let me tell you what I am absolutely certain of: This passage has nothing whatsoever to do with polytheism. Deuteronomy is adamantly and without debate monotheistic!!! Consider Deuteronomy 6:4, arguably the most quoted scripture for the Jews. “Hear O Israel: The Lord our God, the Lord is one.” This is the shema–a passage quoted by all Jews very often. There is NO WAY that Deuteronomy 32:8 has anything to do with polytheism or henotheism. Those who say so are either trouble-makers or are not well-acquainted with the content of the Book of Deuteronomy. There is no henotheism here!!! There is plenty of evidence for God using “sons of God” to apply to humans. Again, it is not even certain that this was the original of Deuteronomy (although I believe it is likely). Either way, there is no henotheism in this passage!
I somewhat doubt that the Septuagint are mistranslating Deuteronomy 32:8. Especially because the DSS has “sons of God” in the Hebrew. But, like I said, whatever the original, there is no henotheism in Deut 32;8.
I have already discussed the divine council idea with you in earlier Q & As. Look back at these, please. It does seem to be a biblical idea, but it is no support for poly or heno theism.
John Oakes