Please suggest me

I got one exact match .net domain with 600 exact global search available to register.The CPC for the keyword is around $9.

Another .org domain with exact keyword with 7000 exact global search available.The CPC according to google adwords tool is just $0.20.

Should I try any of them?

Thanks in advance.

Try both! Throw some content up, build a few quick links, and wait and see if you make any money. Exact match domains can be very easy to rank, especially in bing and yahoo, and even google gives them a little boost. The only way you can know if you can make money or not, is to try.