I bought this solenoid from ebay and was wondering how to power it.

It says 12 volts as you can also see from the picture, but i tested it with putting a 9v battery straight to its terminals for a while, the solenoid and battery got hot after a while.

I measured it with a multi meater and it read 9.0 ohms. Putting the multimeeter through it measured 0.53 amps. Both with 9v battery

If i had battery eliminator that gave 12v output, what other components would i need to make it not go hot? Do i need some resistors?

And is it possible to get its power usage to a minimum with it still opening using various components?

Can i add lots of resistors and the voltage remains 12?