The manual says 87 acceptable, 89 recommended.
Must be a different manual than mine. My 2010 says 87 for all engines except 5.7.
For 5.7 it says 89
All engines (except 5.7L engines) are designed to meet all emissions regulations and provide excellent fuel economy and performance when using high quality unleaded “regular” gasoline having an octane rating of 87. The use of premium gasoline is not recommended, as it will not provide any benefit over regular gasoline in these engines.
The manufacturer recommends the use of 89 octane for optimum performance.