If you work, go to school or have other responsibilities that take you away from the house, a dog of any age 8 weeks and older will be able to be home alone for 8 to 9 hours if he has the right set-up for comfort, safety and to meets all of his needs.
It will take a bit of careful planning and obtaining the right items to ensure that your Pom is protected, cannot get into any trouble, can reach both his food and water, and has the right items to help keep stress and anxiety at a minimum.
Also, it is possible to train a Pomeranian to have more self-confidence about being by himself and to also learn independent play which is a huge part of handling the isolation.
It is not recommended to leave a Pomeranian at home for longer than those 8 to 9 hours because as the time ticks away, there is more of a chance of something happening. Water and food can run out, pee and poo will accumulate in the Pom's designated area, etc.
If you will be gone longer then those 8 to 9 hour or overnight, it is highly suggested to have your Pomeranian stay with a family member or friend. Alternatively, doggie day care or canine hotels for overnights are options if you do not have any volunteers.