you've waited 14 months to see if you'll rank with no content and no backlinks for a 9 million searches per month keyword?? Dang, that is some next-level dedication, even I get sick and tired of waiting for 6-7 months and I'm pretty lazy by nature
Also...
9 million searches a month.
pretty low competition.
... how exactly did you assess the competition to come to the conclusion that it's low? Because, from my experience, most keywords with obscene amounts of search volume like this one are very competitive. Something's not right in your assessment
posted 2 optimised articles and added few backlinks (like 5, lol).
too few articles. Also (probably) too weak backlinks, especially for a keyword with 9 million searches per month
today, my keywords are not even in top 100 (never been)
what a shock, huh! (just being sarcastic

). It's obvious that such a monster keyword is not even in top 100. Who do you think you are to rank a no-name website for a keyword that makes companies millions per year, with only 2 articles and 5 backlinks? Amazon? Forbes? lol
in no particular order (but I'll try to include the most important reasons first)...
1) the obscenely high search volume of the keyword, especially if the keyword is profitable (has commercial value)
2) your absolutely ordinary website. You only rank for such keywords if you know what you're doing, and even then you need a ton of money and patience to rank for such keywords, and you also need a strong website (especially if the keyword is in ultra-tough niches like travel, business, banking, SEO, web hosting, loans, investment, medical, certain sub-niches of the technology niche, certain sub-niches of the self improvement niche, etc). Good luck ranking in any of these niches for a 9 million searches per month keyword with 2 articles and 5 backlinks

3) the niche. If you're into one of the niches I just mentioned forget that you had a website! Go read more about how SEO works, and then try to rank in one of the more accessible niches: hobbies, pets, etc
4) the ultra tough competition that you're facing for that keyword. A keyword like that is only approachable by experienced SEOs with deep pockets, not by mere mortals like you and me