Some translations say [Israel], while majority of the others say [you].
[New International Version] Like a lion they crouch and lie down, like a lioness--who dares to rouse them? "May those who bless you be blessed and those who curse you be cursed!"
[New Living Translation] Like a lion, Israel crouches and lies down; like a lioness, who dares to arouse her? Blessed is everyone who blesses you, O Israel , and cursed is everyone who curses you.”
Other translations https://biblehub.com/numbers/24-9.htm
A previous verse (24:5) speaks of Jacob in most translations, but atleast two translations omit Jacob,
[New International Version] "How beautiful are your tents, Jacob , your dwelling places, Israel!
[New Living Translation] How beautiful are your tents, O Jacob ; how lovely are your homes, O Israel!
[Contemporary English Version] [no Jacob] "People of Israel, your camp is lovely.
[Good News Translation] [no Jacob] The tents of Israel are beautiful
Other translations https://biblehub.com/numbers/24-5.htm
[Genesis 27:29] shows a similar verse to [Numbers 24:9], but the former is of Isaac speaking of Jacob,
[New International Version] May nations serve you and peoples bow down to you. Be lord over your brothers, and may the sons of your mother bow down to you. May those who curse you be cursed and those who bless you be blessed ."
Other translations seem identical, https://biblehub.com/genesis/27-29.htm
Who is being referred to in Numbers 24:9, and what is the reason for the differences (if any)?