Which all goes to prove that the engine won't warm up at idle, even after 9 minutes.
The problem is that when tye engine is cold, the ECU dumps a load of fuel in to keep the engine running. At idle, the spark plugs aren't at optimum temperature, so the spark isn't as good, and the fuel doesn't burn fully. The excess fuel washes oil from the cylinder walls, and may dilute the oil, thus reducing its lubricating ability.
You would all be aware that taxis run forever without an engine faulure. The reason is that basically the engine never gets cold. The greatest amount of damage is done to an engine while it is cold. So forget what Gillie and his old man say and do - just get in, turn on, and go.
There is another thread that discusses the pros and cons (mostly cons) of letting the engine idle to warm it up. The main point I can make here is that if you are warming up by idling, you are burning fuel but going nowhere. No wonder you have shite fuel economy!