In January I will have 9 hours between flights from Santiago airport. Is it possible to go into town and enjoy a short tour?

As long as you leave enough time to get to town and time to check in for your next flight, you should have time to visit the city.
If you are one of the nationalities which pay a reciprocity fee then you will need to pay it to exit the airport. You also need to check if your luggage can be checked through to your final destination or if you will need to store it and check in again, which will also take time.

A short tour, but yes.

Probably 1 to 1.5 hr to exit, & start your return 3 to 4 hours before your flight, depending on if it is domestic or international.

If you are able to check luggage and get ticket for the onward flight before you leave the airport that will get you a bit more time.

That is exactly what we plan to do. We will be going thru Santiago (from Mendoza, Argentina back to USA) on January 2. Thru a travel agent I'm using in Buenos Aires, she gave me the name of a company that will do a tour and pick up and take back to the airport for $75 per person. Their website is SANTIAGO VISION http://store.santiagovision.cl/
I think we will need to tailor it if we use them because we would be more interested in seeing markets, shopping, good lunch rather than just touring the National sites.
Please let me know if you or anyone else finds out or knows of a person that will do a private tour for the day.

Actually, I just found a private tour service we plan to use. Hector Medina, [email protected].

Santiago Vision does good tours from the airport, but if you want a personal service and be able to choose where you go, then Hector Medina is a good choice.

Neilbit, don't miss this point that Huentetu made above:

"If you are one of the nationalities which pay a reciprocity fee then you will need to pay it to exit the airport."

I take it you're a U.S. citizen. If you go into town on a tour, you officially enter Chile and pay the reciprocity fee to the tune of $131 per person.

I thought you had to pay the reciprocity fee just to transit thru the airport. It is a real drawback with 5 of us but it may be the only time in our lives to see Santiago.

No. You don't pay if you are transiting international to international through SCL, which you would be if you were just connecting. That is an extra $650 for your group. Is it worth it? If you plan to back to Chile sometime during the life of your passport, you'll be set

I should say "just connecting and not leaving the international transit area of the airport."

You cannot get through passport control without paying it, even if you are connecting later to another international flight. So you cannot leave the airport without it. If you stay in the transit area you are fine, but you have to stay there for the 9 hours.

BTW the fee is good for the life of your passport.