A public opinion poll published nine days before Israel's general election said Prime Minister Menachem Begin's popularity had grown since his Air Force attacked the Iraqi nuclear reactor. The poll in the Jerusalem Post gave Mr. Begin's Likud-bloc coalition 41 percent of vote. This would be enough to give the Likud 49 seats in the 120-member Knesset and should enable Mr. Begin to muster a coalition with religious and right-wing groups.