Private Sub Worksheet_Change(ByVal Target As Range)
    If Not Intersect(Target, Range("C9")) Is Nothing Then
        On Error Resume Next
        Sheets(Range("C9").Value).Copy
        On Error GoTo 0
    End If
End Sub

Private Sub Worksheet_Activate()
    Dim sSheetList As String, sh As Worksheet
    For Each sh In ActiveWorkbook.Worksheets
        If Not sh Is ActiveSheet And Not (sh.Name Like "*(*)") Then
            sSheetList = sSheetList & IIf(sSheetList = "", "", ",") & sh.Name
        End If
    Next
    Range("C9").Validation.Modify Formula1:=sSheetList
End Sub