[SDPhantom]

This is similar to what I did with my personal nameplate addon. I modified it to duplicate the layout of your existing code. If you're running this on Classic, change the first hook from AcquireUnitFrame to OnNamePlateCreated.

local TextObjects={};
 
hooksecurefunc(NamePlateDriverFrame,"AcquireUnitFrame",function(self,base)
    if base:IsForbidden() then return; end
 
    local uf=base.UnitFrame; if TextObjects[uf] then return; end
    local healthtext=uf.healthBar:CreateFontString(nil,"OVERLAY",FontName);--"NumberFontNormalSmall");
    healthtext:SetPoint("RIGHT",0,0);
    healthtext:SetFont(STANDARD_TEXT_FONT,12,"OUTLINE");
 
    TextObjects[uf]=healthtext;
end);
 
hooksecurefunc("CompactUnitFrame_UpdateHealth",function(self)
    local healthtext=TextObjects[self]; if not healthtext then return; end
    if UnitIsUnit(frame.displayedUnit,"player") or not UnitIsFriend("player",frame.displayedUnit) then
        healthtext:SetFormattedText("%.0f%%",100*UnitHealth(self.displayedUnit)/UnitHealthMax(self.displayedUnit));
    else healthtext:SetText(nil); end
end);