[1966tbird]

The engine will bolt up but you will need the entire engine electrical system and ECM .
You will then need to bond the NEW ECM with your old BCM. Your old ECU will not work. It’s set up for a different crankshaft, crank position sensor reluctor ring….different number of teeth, and the later engine is setup for coil over spark plugs vs wasted spark ignition module. And a few other little tweaks.

 

[1966tbird]

Standard or automatic transmission?
Do you know the mileage on both vehicles?

with a little work, you could upgrade your 06 with many of the 09’s features such as the tire pressure monitors, radio…. Is the 09 the same body as your 06.? 2dr vs 4dr?

 

[1966tbird]

Cool
You will want the entire engine wiring system and the ECM. All should plug in with little difficulty.
Your main problem is rebounding the new ECM to your BCM. Search the forum on how to….
I hope neither cobalts are Ca emissions cars.