You lucky bastard! 90% in organic traffic? Tell us how you did it. Unless you grew from 10 to 19 uniques... (kidding)
Don't worry about the increase in traffic particularly since it is coming from the search engines. Google knows exactly where your traffic is coming from all the time anyway.
Not a problem at all. Adsense will be able to detect the referrer. As long as your traffic is legit, it's all good man.
If you get more traffic from search engines then it's more than great. Key things to note, track your visitors, watch where they come from and what keywords they used to find your website. Using this data you'll be able to get more traffic by optimizing your website content even further.
It doesn't matter as Adsense can track traffic. As long as you don't do anything that violates the rules, you are fine.
dats not at all a problem. it must hav come from a man who must be researchin on something and gets your site. so it is a no issue..!!
Cool for huge traffic from search engine. I think you don't have any problem with it. If still worry, you can have a quick report to adsense team.