Dim x1 As Long, y1 As Long, x2 As Long, y2 As Long

Do
x1 = Val(InputBox("Введите координату первого поля x1"))
y1 = Val(InputBox("Введите координату первого поля y1"))
Loop Until x1 > 0 And x1 < 9 And y1 > 0 And y1 < 9

Do
x2 = Val(InputBox("Введите координату второго поля х2"))
y2 = Val(InputBox("Введите координату второго поля y2"))
Loop Until x2 > 0 And x2 < 9 And y2 > 0 And y2 < 9

MsgBox ((Abs(x2 - x1) = 2) And (Abs(y2 - y1) = 1)) Or ((Abs(x2 - x1) = 1) And (Abs(y2 - y1) = 2))