If you are collecting the data "date" from a Google Form to a spreadsheet and you use Data Merge add-on to create documents, it merges the date but adds the time as well:
- data in spreadsheet: 9/3/2015
- result of merge: Thu Sep 03 2015 13:21:37 GMT+0100 (CET)
To shut off the extra on your merged documents, please select the data to be tagged on your template and choose Format/Clear formatting from the Google tool bar. Your merged documents will then just show the time as shown in your spreadsheet.
If you are still getting all the extra on your merged documents, select the cells in your data source sheet and choose "Plain text"