a) No you will not be able to login to the server as the “root” user.
b) If you were allowed to log in as root, you could manipulate other users’ files. The server you are on is shared and, as such, each user may only manipulate their own files (and, in some cases, files within their group if those files have appropriate permissions settings)
The user/pass word you are provided allows you to login to FTP, and if you have identified that user as a “shell” user you may ssh to the command line, where you will be able to manage files that you own in your user space, but you do not have root privileges.
If you are trying to use ssh to log into the shell, make sure the user that you are trying to login as is a “shell enabled” user. By default, the users that DH establishes for you at sign up time are not authorized shell access, they are only FTP users. You can make those users “shell enabled” from with the control panel: