Yes you can stew them now and freeze the result! Heres a recipe for Apple Jam using Cooking Apples Below
Ingredients
6 lb. cooking (tart) apples
2 pints water
Rind and juice of 4 lemons
1 1/2 oz ground ginger (optional)
6 lb. sugar
Method
1. Peel, core and chop the apples.
2. Tie the peel and core in muslin and put with the apple and water into the preserving pan.
3. Add the finely grated lemon rind and the juice, together with the ginger if used.
4. Cook until pulpy, then squeeze out and discard muslin bag.
5. Stir in the sugar and boil until setting point is reached.
6. Remove from the heat, skim, pot, cover, and label.
Hope this helps!