Hi,
try this quick and dirty solution:
string str1 = "3:20 PM";
DateTime time1;
if(DateTime.TryParse(str1, out time1))
{
DateTime time2 = new DateTime();
time2 = time2.AddHours(9);
time2 = time2.AddMinutes(15);
if (time1.TimeOfDay > time2.TimeOfDay)
MessageBox.Show("Time is later");
}