Set a Havahart trap on the porch, and put the cat food inside of it.
And take the cat in the house.
Next morning, shoot the 'coon between the eyes with a CCI CB short from yor choice of .22 LR, and drop the 'coon in a trash bag for disposal.
But as long as the food's on the porch, there will always be another 'coon to eat it. Move it inside, and you won't have to worry about it.
Oh, and secure any "pet" doors to keep them out of your house.