The "me." portion is just a shorthand notation for the current form. It represents forms!yourformname. If you are doing anything in code with the current form or a control on the form you can use the "me." shorthand. If you are executing code from one form that impacts a second form then you have to use the full form reference notation for the second form.
The reason you are getting the times repeating is that somehow you are not providing the day number to the query used for the combo box; specifically the WHERE clause shown in red below.
Code:
SELECT qryAvailableTourTimes.longDayNumber, qryAvailableTourTimes.dteTime FROM qryAvailableTourTimes WHERE (((qryAvailableTourTimes.longDayNumber)=Weekday([mydate]))) ORDER BY qryAvailableTourTimes.longDayNumber, qryAvailableTourTimes.dteTime;
Also, the code: Me.Combo9.Requery should go in the After Update event of the text box where you enter the date not in the After Update event of the combo box