Ravi,
Please look into the profile parameter -
login/password_max_idle_productive -
Specifies the maximum period for which a productive password (a password chosen by the user) remains valid if it is not used. After this period has expired, the password can no longer be used for authentication. The user administrator can reactivate password-based logon by assigning a new initial password. Permissible values: 0 – 24,000 (unit: days); Default value 0, that is, the check is deactivated Available after SAP NetWeaver 6.40
Your objective of preventing users from logging after 90days of inactivity can be handled easily by setting the value to 90 for this parameter. I don't think you need to reinvent the wheel for this by creating ABAP reports etc.
Regards,
Shivraj Singh