No. The Jetpack plugin was created to appease WordPress.ORG users who were peeved because we WordPress.com bloggers had features that were not available to them. To please them WordPress developers created the Jetpack plugin to create parity between users. Moreover, it has sweet nothing all to do with access to metadata. We cannot access metadata on free hosted WordPress.com blog.
I need to specify my meta description and title as part of a seo competition
When it comes to SEO gaming here at WordPress.com take a deep breath and hire a web host now, so you can set up a self hosted WordPress.com install as that activity here is not allowed and will get your blog suspended.
SEO blogs: Blogs that are written for search engines instead of humans. These blogs are dedicated to trying to fool Google and other search engines into ranking them or the sites they link to highly. WordPress.com is not meant for this type of activity. http://en.wordpress.com/types-of-blogs/