Why do you think there's a sandbox? It doesn't make any sense to me. Maybe it just takes time to make a site high quality enough to rank for those competitive keywords. If you expect to rank high for competitive keywords before "9 months" then you're either doing something blackhat or you're doing something which Google detects as blackhat. Why does it make sense that there is a sandbox?
Because Matt Cutt's said there was, although he said Google doesn't call it that, and that it doesn't apply to all keywords. Anyone with years of experience knows it exists.
The most common answer is probably to prevent new sites from trying forbidden techniques in order to take top positions in SERP. There is such thing as "domain authority" and this index is created for a purpose - to show Google how important, useful and unique a particular website is. When you start with a brand new site (domain) first you need to prove Google your intentions are serious and this will not be the next spammy website in the Internet. That's where sandbox comes. It's like a filter which separates the new (unknown) sites from the rest. And the period is not necessary 9 months. IMHO it could well be 1 month or less if your content is unique, highly relevant (a very specific niche, for instance) and if you build your links slowly and they're quality... I don't see any problem here
I don’t know if there is a sandbox or not but I launched my first site about a year ago and was stuck on page 42, no matter what I did I didn’t move, then nearly 6 months to the day that the site went live it went to page 8. And has been creeping up ever since.
the sandbox is simply a deterrent. it is quite frankly a rather difficult status to achieve. however, people often jump the gun and assume they've been placed in the sandbox. then they come ranting and raving to the internet forums trying to figure out how to get out and thus increasing the attention and myth of commonality of the sandbox. You have to be doing some seriously dirty mass backlink automation from what I've seen to get yourself boxed. I am quite aggressive with my backlinking strategies for my new sites and I've never had an issue.