How to send BUY/SELL order exactly at 09:00:00.000 to BSE/NSE exchanges?

Pl let me know how can I place Buy or sell orders at exactly when the market opens at 09:00:00.000 hrs and at 09:15:00.000 for SME scripts. Can any one help in this regard? Any Algo code or any other procedure to place such orders?
Thanks and regards

Use AMO ( after marker order) and maintain the trading balance.