How can I redirect the users after confirmation basing on the roles they have?
yes, with Rules!


create a new rule. 
select event: user has logged in (or if you use LoginTobogan module you can use the event "When the user account is validated".)
select condition: User has role(s), and assign the role (I recommend create a new Role and assign this role to a test user)
selet the action: Page redirect, and add the url to the destination
(I have selected 'Immediately issue the page redirect' to see the redirection (if is not select this, I can not see working the redirection, but test if you does not need this. Please review the warning about the setting)
enable your rule and test.