I am currently reviewing a Drupal site I am taking on for a client. My first task will be to make sure it's all up to date as the site was hacked recently.
Currently it is on version 7.9 - what it is recommending me is 7.34. 7.34 is the currently recommended stable release as per the Drupal site. What is this 7.9 version? Was it an old beta or dev version? What version should be used?
Drupal 7.9 is not "Drupal 7.90". This version is older than Drupal 7.34.
I recommend you to upgrade the Drupal core from 7.9 to 7.34 for performance and security reasons. Check first if is possible. Some developers hacks the Drupal Core, which is a very bad practice.
If you want to see all the changelog, you can see this article: https://www.drupal.org/node/3060/release?api_version%5B%5D=103