Sub Bunka_do_Poznamky()
    Dim x_rng As Range, c As Range, x
    
    Set x_rng = ActiveSheet.Range("A1:A9")
    
    For Each c In x_rng
        x = Trim(c.Text)
        c.ClearComments
        If Len(x) > 0 Then
            c.AddComment x
        End If
    Next c
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim x, c As Range

On Error GoTo xErr:
    Application.EnableEvents = False
    
    Set c = Range("A" & CStr(Target.Row))
    
        x = Trim(Target.Text)
        c.ClearComments
        If Len(x) > 0 Then
            c.AddComment x
        End If
    
    Application.EnableEvents = True
    Exit Sub
    
xErr:
     Application.EnableEvents = True
End Sub