When buying a tag for whitetail, do I have to hunt/harvest it in the zone I said when I bought the tag? Say Im hunting in zone 6 one week and didn't get anything can I hunt in zone 9 the next week?

No, you can hunt for whitetails in mulitiple big game management units and are NOT restricted to zones like elk hunters are.  So, yes you can hunt whitetails in say Unit 19A from Oct 10 - Oct 31 and if you are unsuccessful, you can hunt whitetails in Unit 11 from Oct 10 - Dec 1.  Your whitetail deer tag is valid for whitetail deer only, for any hunt listed under "2013 Whitetail Deer Tag Seasons" on pages 21-24 of the 2013 Big Game Seasons and Rules booklet.