If you cover chapter 9 you should be able to edit the account attributes of the employee (to be honest, I have not tried the instructions provided in the course). If it does not work, you could check if the account object is created and associated to employee.
I did download the module package from chapter 9 ( from introduction) and I was able to edit the account attributes of the new employee I was trying to create. So, at least the package works as expected and you could explore that further to identify the differences between the one you have vs the one you can download. You can always provide your feedback to the Mendix team and they can correct if you find any discrepancies in the instructions provided.
Hope this helps!
Good luck :)