The 09 requires synthetic per GM?
No. dexos 1 was not used until the '11 MY. From the '09 manual:
Engine oil which meets GM
Standard GM6094M and displays
the American Petroleum Institute
Certified for Gasoline Engines
starburst symbol. To determine the
proper viscosity for your vehicle’s
engine, see Engine Oil on page 5-15.
Use only an oil that meets GM Standard GM6094M.
• SAE 5W-30
SAE 5W-30 is best for the vehicle. These numbers
on an oil container show its viscosity, or thickness.
Do not use other viscosity oils such as SAE 20W-50.
• American Petroleum Institute (API) starburst symbol
Oils meeting these
have the starburst
symbol on the container.
This symbol indicates that
the oil has been certified by
the American Petroleum
Notice: Use only engine oil identified as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certified For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
the vehicle warranty.
Cold Temperature Operation
If in an area of extreme cold, where the temperature
falls below −20°F (−29°C), use either an SAE 5W-30
synthetic oil or an SAE 0W-30 engine oil. Both provide
easier cold starting for the engine at extremely low
temperatures. Always use an oil that meets the required
specification, GM6094M. See “What Kind of Engine
Oil to Use” for more information