WELCOME BACK: We knew this was gonna happen. Beverly Hills, 90210producer Aaron Spelling is rumored to have had a change of heart and will allow Shannen Doherty to return to the Fox series next fall. According to a source, Doherty has been on best behavior since Spelling refused to renew her contract in December. The source says Spelling realizes how valuable Doherty is to the show but plans to clear her return with the other cast members before writing her back into the series (though her publicist denies she's returning). In the season finale, scheduled to air May 25, Brenda runs off to drama school in London-though not before a final fling with Dylan (Luke Perry).