As above, you have no hope is going to all those places in 8-9 days. Even 8-9
weeks would be better.
The day of arrival and day of departure will be wasted days.
It will take longer than you think to get between destinations. The roads are mainly 2 lane & twisty: no freeways at 60 mph/100kph
There are bus's but the only SI passenger rail is Christchurch to Greymouth
You may not be able to get to places like Arrowtown & the glaciers without a car.
Dunedin & Oamaru are not worth stopping at.
Note Easter weekend is 30 March - 2 April. Places like Queenstown get sold out. There is also a big
air-show at Wanaka (near Queenstown) that weekend
For 8-9 days you need to be realistic on what you can see
Edit:
Some good realistic posts here
New Zealand for 8-10 days
Including
post 30 and post 35 as quote below