Returning from beginning of mist of Pandora. And I noticed a lot has changed like level squish all my characters are low levels now. And I noticed there was an gear update option is that a good thing or a bad thing I just don’t want to mess up my characters. Not worried about bar resets or anything like that because don’t remember them anyway I’ll have to learn all that again just don’t want to mess nothing up
Welcomae back!
Yes, it can be a bit overwhelming, coming back after so long. It’ll be fine; just give yourself some time to re-adjuat. 
Gear Update won’t lose anything.
It gives you new gear. but also mails all of your old gear and bag contents to you.
So just be sure to check your mail after logging in, and sort out your new and old gear and other stuff.
Thx for info
Returning after 9 years but game crashes every time I try to get on main, all others work fine, any ideas how to get this sorted out?
All others work fine?
Did you reinatall WoW? I assume so, after 9 years. If not, maybe reset your UI as described at https://eu.battle.net/support/en/article/7549
Otherwise, try the Stuck Character service
https://us.battle.net/support/en/help/product/wow/197/834/solution