Preheat the oven to 350 degrees F. Spray a 4-quart shallow casserole dish with cooking spray.
Place a large skillet over medium heat. Add the sausage and cook, breaking it up with a wooden spoon and stirring occasionally, until brown, 8 to 10 minutes. Remove the sausage with a slotted spoon to a paper towel-lined plate. Drain off all but 2 tablespoons of the sausage drippings. Add the butter to the skillet, then add the celery and onions. Cook, scraping up any brown bits that are on the bottom of the skillet, until the vegetables are soft and translucent, 5 to 7 minutes. Add the poultry seasoning, salt and pepper and cook, stirring, for 2 minutes more.
Transfer the vegetable mixture to a large bowl and add the cornbread and reserved sausage. Add the chicken stock, cherries and eggs. Stir to coat gently and soften the cornbread. (Do not overmix or the cornbread pieces will turn to mush.) Transfer to the prepared casserole dish.
Bake until the stuffing is set, about 35 minutes. Let cool for 10 minutes before serving.