I spent almost a whole month there, solo trip, it was about 6 years ago, but it shouldn't have changed too much.
Places I went include (I went in an anti-clockwise direction) :
Launceston and surrounds
Beauty Point
Cradle Mountain NP
Mole Creek
Stanley
Marrawah
Strahan
Derwent Bridge
Hobart and surrounds
Mount Field NP
Bruny Island
Geeveston
Freycinet NP
Richmond
Port Arthur HS and surrounds
Bicheno
Hollybank
If you are an experienced driver capable of handling a large vehicle, you can hire a rental mini-bus, but with 8 passengers, luggage may be a problem - probably better to split into 2 vehicles for comfort.
There are tour companies that can take you around specific locations like Cradle Mountain and Mount Fields NPs for example.
Those are day trips, they will pick up your group in the morning, drive to the location, and depending on the agreed itinerary, explore the area on foot.
You'll usually complete the day tour by late afternoon when they drive you back to your accommodation.
When planning activities, make sure you have enough time to travel and see the attraction - travelling distances are usually quite long.
Seeing the whole island is possible, but it involves A LOT of driving, and a fair amount of time.
If you are asking about hiring someone to
literally drive you around the island - I personally don't know anyone who does that - you'll be paying someone to travel on holiday with you as your personal tour guide & driver.
PM me if you want the day tour company I used.