What to do if 9 month old female, Peekapoo has started to "poop" in house within 5 minutes of returning from successfully pooping and urinating outside? (We spend 20-30 minutes outdoors each time)

It's time to retrain her.

Many dogs this age fall back on their potty training. Many things can cause this. A change in the household, illness, separation anxiety, lack of exercise.

The first step would be to take your dog to the vet to make sure this isn't due to illness. If her bill of health is clean then you need to go back to basics. Take her outside, wait for her to potty saying your potty command, then tons of praise when she goes. When she potties in the house a firm "NO!" and take her directly outside so she understands where you expect her to go.

Is she spayed?