8b is fine for cold hardy kiwi. A freeze after bud break in spring can cause a little damage, not too bad. You will need a stout trellis. I used cattle panels. these put on a LOT of foliage.
Do not fertilize the plants much, just a little compost is good for massive crops. I would test your soil PH. Mine is slightly acidic, kiwi just don't like alkaline soil.
prune them back every winter to a few buds on each spur like you do with muscadine grapes.