Upvote:0
Jacob IS Israel (Genesis 35:10), so Jacob and Israel is often used interchangeably, meaning the descendants (or people) of Israel. As for "you" in Numbers 24:9, this is also referring to the people of Israel who are addressed here. The whole people is referred to as one person "Israel/Jacob" who is their forefather.
Upvote:3
The word "Israel" is not found in Numbers 24:9 in the Masoretic Text (Hebrew), the Septuagint (Greek), or the Vulgate (Latin), which is why most translations do not include it in this verse. But, as you noted, the beginning of the chapter makes it clear that the prophecy/message is about the people of Israel. Jacob is another name for Israel, and both names are used in verse 5.
Balaam is delivering this message in the presence of Balak, king of Moab. If you only look at the second half of verse 9 and you read "May those who bless you be blessed and those who curse you be cursed!", you might think that he is blessing Balak. However, it is clear from the entire message that "you" refers to the people of Israel, not to Balak. Balak understood this, because he gets angry with Balaam in verse 10.
Presumably to avoid confusion, the New Living Translation decided to explicitly clarify that "you" in verse 9 still refers to Israel.