Hi,
Depending on your usecase and license it might or might not possible(have not tested those options myself):
If you have a platinum license you can try the document level security to restrict the access for the user to documents from the last 90 days.
Otherwise, you might want to try filtered aliases to create an Alias on the Index containing only the last 90 days and grant access to this alias instead of the original index. Downside: The alias acts as an index so if you have visualizations they would have to be updated to point to the alias.
Best regards
Wolfram