Probably due to car sitting around and not driving it
With only 8,000 miles on a car that is that old probably means it has not had it's oil changed much if at all. The acid in the oil deteriated the gasket and probably a rear main seal ( Hope not) Just replace the gasket and change the oil at least every six months even if it does not get driven much.
It is not that the oil goes bad but the additives in the oil do and cause the problem you have.
If your car is a 2009 it means you only go 2,000 miles a year. That means a lot of the time the car is just sitting.
A lot of exotic cars are not used and have the same problem as well as cars in a museum.
This is why it is always suggested that you put fresh oil in a car that is going to be stored for a long term. Also why not to start a long term stored car and let it idle (EVER) while being stored.
Just get a gasket and start changing the oil every five or six months no matter if it does not have a lot of miles and stuff like this won't happen.
Like this guy said:
"These cars are meant to be driven", so enjoy the hell out of all of it - not just the look of it when it is all clean" - Carroll Shelby
2012-candy red- V-6 MCA, Automatic Trans. CFM Valve cover breather. MMD blackTail light trim.Magnaflow axle back street mufflers, JLT oil catch can.MMD hood struts.
Airaid Cold Air intake. red caliper covers, 3.7L performance engine cover, Flat black hood spears.Boss 302 strut brace, CDC rear panel, Trunk Cargo net,--Dash carpet cover,
Viser stickers to cover ugly yellow warning crap,Aluminum driveshafft and Swarr Bar.