Hours which are past midnight are suffixed with next day date. In Panchang day starts and ends with sunrise.
Balidan on Maha Navami should always be done on Uday Vyapini Navami. According to Nirnaysindhu, the best time to perform Balidan is Aparahna Kala.
It should be noted that Maha Navami fasting and Puja might fall one day before Durga Balidan depending on the start time of Navami Tithi on the previous day. If Navami Tithi starts before Sanyakal on Ashtami Tithi then both Ashtami Puja and Navami Puja are done on the same day i.e. on Ashtami Tithi. If it happens then Ashtami Puja, Sandhi Puja and Navami Puja are done together on Ashtami Tithi. However Durga Balidan is always done on Navami Tithi.