Yes, of course, you can add as well as modify the timing option for the specific date of the trip using WP Travel Pro plugin.
WP Travel Utilities module provides the feature of adding multiple fixed departure dates with multiple times(in hour).
If the trip is available for different time slot in single fixed departure date, then you can use this feature to provide the available time slots for the date of the trip so that customer can choose time slot for the trip as per their requirement.
You can add any number of times(in hours) for the specific date of the trip by going to Admin Panel > Trips > Individual Trip(edited trip) > Dates and Prices
For detail assistance regarding timing option, please refer link of our official documentation.
If you have any confusion then please post them in our official support forum.