Pros
higher compression means, more low end torque, better throtle response and faster spool up.
Cons
A little harder to tune and more dangerous to run higher amounts of boost.
8.0-1 Pros: Run higher boost with less knock and less knock with pump gas.
Cons: Not as much low end torque or throtle response, slower spool up.
If that clears anything up...your welcome...if you already figured it out...good
Personally I would probably pick 9.0-1 not really that big of a difference...and if your using forged internals...why not?