You will need a second macro to fire automatically as you open the document. If you have both macros in the ThisDocument module they would be...
Code:
Private Sub Document_ContentControlOnExit(ByVal ContentControl As ContentControl, Cancel As Boolean)
If ContentControl.Tag = "Checkbox1" Then
ActiveDocument.Bookmarks("Test1").Range.Font.Hidden = ContentControl.Checked
End If
End Sub
Private Sub Document_Open()
Dim aCC As ContentControl
If ActiveDocument.SelectContentControlsByTag("Checkbox1").Count = 1 Then
Set aCC = ActiveDocument.SelectContentControlsByTag("Checkbox1")(1)
ActiveDocument.Bookmarks("Test1").Range.Font.Hidden = aCC.Checked
End If
End Sub