My 2009 cobalt would not shut off and key would

If this is any help my car did the same thing several times and dealer wanted to charge you an arm and a leg to fix so check this the fuse box by the floor board on passenger side remove cover and check the ignition fuse mine was blown so i had to replace it so hope this works for u.

Try turning steering wheel and jiggling key or pull tilt adjustment and move up and down and jiggle key toward off position if no good notify dealer of problem notify even if u get key off vehicle is 09 should be still under warranty if happened once will do it again