Former Secretary of State Henry Kissinger wound up his short private visit to Israel with an intensive round of meetings with Israeli leaders. After touring the Old City of Jerusalem, Mr. Kissinger, due to leave for Saudi Arabia today (Jan. 6) on the next leg of his Middle East tour, said he supported the unification of Jerusalem. Earlier he called on President Yitzhak Navon and met Foreign Minister Yitzhak Shamir. He also had talks with former Foreign Minister Moshe Dayan, but said he could not at this stage agree with Mr. Dayan's idea of granting autonomy unilaterally to the occupied areas. More exchanges were needed among Prime Minister Menachem Begin, Egyptian President Anwar al-Sadat, and president-e lect Ronald Reagan, he said.