I would like to ask, once the blog has been crawled, there's a chance that I can see it already in the SERPs?
Yes you can see it and may be in the first page with the help of long tail keywords depending on google algorithm and the quality of content.
Content is the king. Google loves fresh content with keyword rich content. If you have in your blog, then it may be indexed by Google.
Yep it is possible but only if your content is very informative and unique. You should have very fresh content for your blog post. It is my experience that if all needed things are exist in the post then definitely you post will get rank in SERPs with your main keyword.