Preheat oven to 400 degrees F. Slice squashes in half lengthwise and scoop out the seeds. Rub the flesh with olive oil and place squash halves cut side down on a baking sheet. Bake in preheated oven until slightly tender, about 30 minutes.
Meanwhile, in a large skillet, brown ground pork with sage.
Pulse carrots, celery, onion, and garlic in food processor until you have an even dice (or you can do this by hand). I prefer my veggies to be as small as the rice, so I just use the food processor. Add to the pork while its cooking. Stir to combine and continue cooking until the vegetables are tender and the pork is brown and crumbly.
Add white wine to hot pan and scrape the bottom to deglaze. Allow to cook for 1-2 minutes until wine reduces. Remove from heat.
Stir in wild rice, kale, apple, and salt. Taste mixture and add more salt as desired. Don't worry - the kale is a bit overpowering raw but once cooked it blends in perfectly.
Divide the mixture into 4 equal portions and mound into acorn squash cavities. Use hands or back of large spoon to make a compact mound.
Place stuffed squashes in the 400 degree F oven and cook for another 20-30 minutes until the tops have browned and the squash is fork tender.
Serve as a side dish or alone as a meal.