It is completely acceptable for you to feed your hamster blueberries, as long as you do not feed too many of them to your pet at one time.
Hamsters like any other animal need variety in their diet, so you will want to make absolutely certain that you do not give them more two or three at one time. You will also want to make sure that the blueberries are cut in half, depending on the size of your hamster.
Blueberries contain a lot of things that are good for the body, even for animals like hamsters. There are certain vitamins, minerals, and antioxidants in blueberries that are especially good for the body and can even help to fight off cancer.