Hello & Welcome to JA,
Sounds like you have done the pelimary testing. This could be the answer.
PIP3423F: DTC P0016 P0017 P0018 P0019 P0008 P0009 - (Feb 20, 2012)
This PI was superseded to update model, model years and engine RPO codes. Please discard PIP3423E.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
For 2007 model year vehicles with 3.6L LY7 or 2.8L LP1 engine, refer to bulletin 07-06-01-013B for Buick Lacrosse or Allure and Cadillac CTS, STS, SRX or bulletin 07-06-01-014 for GMC Acadia, Pontiac G6, or Saturn Outlook and Aura.
The reluctor for the crankshaft sensor pressed on the crankshaft may have moved.
Refer to attached photographs for exact location. If the reluctor has moved then replace crankshaft.
1= The actual measurement of a good Reluctor wheel.
25 to 26 mm this measurement is from the end of the machined flywheel to the edge of the tooth.
2 and 3= Show a good reluctor next to a bad reluctor
Crankshaft with bad reluctor wheel.
Note: The distance can be offset either clockwise or counter clockwise. Both will result in these codes.