Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Button2.Visible = False Then
Button2.Visible = True
Button1.Visible = False
Button2.Text = Button1.Text
Else
If Button4.Visible = False Then
Button4.Visible = True
Button1.Visible = False
Button4.Text = Button1.Text
End If
End If
cek()
End Sub

setelah itu kita lanjutkan ke button2 sampai button 9, sintak'a seperti ini...

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
If Button1.Visible = False Then
Button1.Visible = True
Button2.Visible = False
Button1.Text = Button2.Text
ElseIf Button3.Visible = False Then
Button3.Visible = True
Button2.Visible = False
Button3.Text = Button2.Text
ElseIf Button5.Visible = False Then
Button5.Visible = True
Button2.Visible = False
Button5.Text = Button2.Text
End If
cek()
End Sub

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
If Button2.Visible = False Then
Button2.Visible = True
Button3.Visible = False
Button2.Text = Button3.Text
Else
If Button6.Visible = False Then
Button6.Visible = True
Button3.Visible = False
Button6.Text = Button3.Text
End If
End If
cek()
End Sub