An 8 month old puppy will usually need to poop around 5 to 6 times per day depending on the type of food they're eating and how much dog food the puppy is eating as well.
The more the puppy eats the more often the puppy will likely need to poop.
Although it is normal if the puppy goes a day or 2 without pooping but they usually do poop up to 5 to 6 times per day.