I am not sure I understand what point you are trying to make here. My first reaction is "so what?"But this "Hebrew of Psalm" is younger than the use in the NT.
[/QUOTE]What about this translation:
"Because of this God - your God! - has anointed you with oil"[/QUOTE]
It is still vocative of address and should be rendered as "Because of this Oh God, your God has anointed you with the oil..." It is the exact same construction as verse 8.