No you can't do that with Agenda: widget+ it either shows a list of month but then in the month view you only see dots not even appointments below the month view and not in the month view.
There are other widget out there which have the option you are looking for I think but I'm not sure if they are updated to iOS10. You have to check the App Store description for that/check last updated or contact the developers. See also the old
iOS8/9 widget topic and if you search for 'Calendars' you get a pretty long list of widgets/apps with a calendar widget. Not all have a month view + description in the month view though. Maybe send a review to the developers of Fantastical, Pocket Informant or miCal to implement this.
It looks like these have it but I'm not sure if they offer iOS10 support for the widget:
Pocket Informant calendar (
iOS10 ready) - month view + below appointments for a certain day
Fantastical 2 for iPhone (iOS10 ready) - month view + below appointments for a certain day
miCal (not yet updated for iOS10 though, old UI)
Eventail (not yet updated for iOS10 though, old UI)
Widget Calendar (not yet updated for iOS10 though, old UI)
Study Cal (not yet updated for iOS10 though, old UI)
Calendarique (not yet updated for iOS10 though, old UI)
Agenda+ (not yet updated for iOS10 though, old UI)