My brand new 2009 Highlander has this high pitch whining noise right from the start. It happens when decelerating, like if you go on a little hilly road, once you get to the peak and then just let gas pedal go so the car just glides down the hill, you will hear this high pitched noise, very high, like airplane landing, but not very loud. What's going on? Took to a dealer, they said it's "normal" operating noise. ????

Check your power steering fluid.

bettr get a new timing chain-will break soon and hurt motors valves--put a new water pump and engine seal at same time-save$--hav an xperiencd independent du the job--dealers are usually troubl

A high pitched whine like that indicates a bad bearing. Water pump, power steering pump, accessory belt slipping, alternator bearing, or in the worst case scenerio, Transmission pump.

may be your power steering pump whining. Check fluid first, then if it's up, start the car up and have someone turn the wheel back and forth a few times. Listen to see if there is more or less noise when this happens. Does the noise go away after it warms up?

It is a wheel bearing, no doubt.
the wheel bearing is pressed in so if you do the job yourself you will need to take the hub somewhere to have the new bearing pressed in, but 100% the bearing.

The noise you're hearing is the electric fuel pump in your fuel tank.

Here are the common causes or rear end noises
Constant high pitched whine at all speeds: Pinion Bearings or Ring gear carrier bearings
Whine at steady speeds or whines on deceleration: Rear end gear set is worn and will need to be replaced.
Rumbling type of noises are caused by wheel bearings or a tire with a separated cord.

take it to a mechanic you can trust and see if it is the wheel bearings

The high pitched whine in reverse sounds normal for a honda. Ever honda I have had makes a similar noise while in reverse. The spinning, scraping noise in drive is not normal. You might want to see a mechanic about that.

This Noise Description sounds Indicative of the Sounds that come from the Serpentine Belt Or Related parts such as Belt Idler Pulley or Belt Tentioner witch also has a Pulley, but if Tensioner itself is Literally BROKE I've replaced a number like this it will cause a Whining noise . Best case scenario its just the Belt, and if any of the other Problems turn out to be the Culprit the Belt MUST be Replaced Anyhow as Damage is Being caused By the Very Whining you hear.
PLEASE Spend the Extras $ for the BEST BELT as this Drives your Water pump, Alternator, A/C Compressor, Power Steering Pump All Crucial to Control of, easy Steering ,All Electrical-Power Distribution, The COOLING of Engine << VERY CRITICAL Component
The Pulleys usually have a more Hum type Whining. So I would say at Best The BELT , And WORST Belt Tentioner is Broke