Welcome to YT and congratulations on becoming the mommy of a morkie! Chase is a cutie! You are going to have so much fun with him.
I also work full-time and have two puppies. I always had someone at home with the puppies the first few months we got them. My daughter is still home during the day with them to let them out of their crates to go to the bathroom and to interact with them so they aren't penned up for 8 - 9 hours straight.
I hope your mom knows that it is going to be hard to take care of the new puppy along with your two children. When my grandchildren come over, I have to watch them constantly around the puppies so they don't squeeze them too tightly, don't drop them, don't kick them when running around, etc.
Yes, your vet is right that a puppy can be taken from its mother at 8 weeks of age, but I would have to agree with others that it really isn't the best time to take him from his mother. I also think you should ask your breeder if they could keep your puppy for a few more weeks. Yorkies and morkies are so very small at 8 weeks plus as others have mentioned, they learn bite inhibition and toilet training from their mother around this age. Even at a few weeks older, I had to give my one puppy nutrical on more than one occasion because her blood sugar went low because she wasn't eating and she had been doing too much. If I hadn't have been there to do that, I hate to think what might have happened. Just something for you to think about.
I know you and your family are going to have a wonderful time and make many happy memories with Chase. I am so happy I have my two puppies; I don't know what I did without them