Are you SURE you checked the oil level?? The dipstick in front - not the tranny oil dipstick in the back of the engine?? The other thing I've seen is that if the car is real new, the very clean oil is hard to spot - and you may not see the oil level on the dipstick and add oil that is not needed.
Either way, you had too much oil in the engine - obviously because you got 9 quarts out - unless you drained the transmission, which happens to take about 9 quarts -
and that much of an overfill would result in oil foam being drawn into the engine, causing fouled plugs and misfires. You migth even have blown some seals if the oil was that overfilled. Better take it to Subaru, let them pull the codes and figure out what is wrong.