The point right now is our ambient is around 26-27 deg. Hence thought a 9 to 10 deg CPU idle temp is high
To be honest I think that is about right. For example here in the UK at the moment, my ambient temp is about 18°C but my CPU is running at 25°C which as a 7°C increase over ambient, but I am using one of the largest Air Coolers on the market. When I was using the Stock Cooler my temps were about 15° - 20°C above ambient!
Still well within the specified range of the CPU but too high for my liking, hence the change of Cooler.
I really do not think you have anything to worry about and apart from going to a refrigerated water cooling system and the extra expense and modifications that would entail, there isn't much more that you could do to bring your temps down further. One of the problems of living in a hotter country I guess.