TOKYO, Feb 29 (Reuters) - Japan's leading share index is expected to open higher on Wednesday on the back of Wall Street gains, extending its more than 10 percent rally this month as it heads for its best February performance in two decades. The Nikkei was likely to trade between 9,700 and 9,850 after hitting a fresh seven-month closing high in the previous session, strategists said. Nikkei futures in Chicago closed at 9,785 on Tuesday, up 25 points or 0.3 percent from the Osaka close of 9