First you say you have checkboxes attached to a query (Bounded), then you say they are Unbounded. Which one?????
If they are Unbounded (in design view, click on the checkbox, bring up its' property sheet, click the All tab and look at the option Control Source. If the box next to it is empty, then it is unbounded), then create a command button, on its' property sheet click the Event tab, click next to the option OnClick, click on the button with three dots, select Code Builder. Then just type in between Private Sub and End Sub:
Me![Check9].value = true
Replace Check9 with the name of your checkbox.