Itinerary Check: 9 day in Kyushu North(?)

I have a trip coming up to Kyushu and I’m probably trying to fit way too much into this trip. I already reluctantly removed Nagasaki from my plan trip, but I’m not sure if still aiming for too much.

Day 1: Arrive in noon in FUK. I expect to be out in Fukuoka/Hakata by 3pm. We’ll probably take it easy and just walk around and eat 5-7 different small meals and call it a night.

Day 2: Head out early to Beppu by train and drop off our luggage at an onsen hotel, meeting up with some friends who will already be there. Head out to the African Safari (11am-4pm) by bus, and finish off the day Beppu town and the onset.

Day 3: Eat breakfast at the hotel, go to Yufuin at the for the jigokus and some sightseeing. Will go to back to the onsen hotel for dinner.

Day 4: Get a rental car in town (Beppu) and head to Miyazaki.

Day 5: Spend half a day in Miyazaki, and head out to Kumamoto and finish the night there.

Day 6: Visit tourists spots in Kumamoto.

Day 7: Visit Mt. Aso and the surrounding area for nature sightseeing. I expect to be done around 4pm. Gead back to Fukuoka and drop off the rental.

Day 8: Spend the day in Fukuoka trying to hit up Nokonoshima, Lalaport, Outlets, and the Nagahama Fish Market etc..

I understand that Miyazaki is not a close distance, and the stop at Mt. Aso would make it an awkward position as it sticks out like a sore thumb not being en route to a Fukuoka, which makes my route a bit all over the place. Would my basic outline be doable with our limited time, or should I take Miyazaki out? If Miyazaki is worth heading to, is there anywhere in my trip that I should take out so I can hit all of the spots? Clearly I haven’t filled in the details of my last 4 days so I am always open to recommendations and advice.

Thanks in advance.