We are in the process of selling a house in Oregon and the inspector noticed that the garage door opener was plugged int the ceramic light fixture. The request that a outlet be installed for this purpose. Can we branch an outlet off the light or do we need to have a dedicated circuit for the opener?

Replace the light fixture with a receptacle. That is what the inspector requested.

I agree with MB but I have a question about that light, is it controlled by a switch or a pull string?

Good question, Ballengerb. If it's switched, the switch becomes the disconnect.

The light is controlled by a switch.

The receptacle outlet for the garage door opener (GDO) doesn't need to be dedicated. I recommend you find power from a 120v (15 or 20Amp circuit) source, and install a receptacle outlet.
If it's the only light in the garage, then it wouldn't make sense any how. If you have access above the garage ceiling, then this is a simple install for the everyday professional.

Is the receptacle on the light hot 24/7 or just when you turn on the light?

The receptacle is hot 24/7, which is why I was interested in branching off it.

OK, then you can drop the ceramic fixture from the box and make a tap for another receptacle. Once the box is exposed please tell us what wires you see, colors and numbers and what is hot.