Digit9
final case
class Digit9[N1 <: Base, N2 <: Base, N3 <: Base, N4 <: Base, N5 <: Base, N6 <: Base, N7 <: Base, N8 <: Base, N9 <: Base](_1: Tag[N1], _2: Tag[N2], _3: Tag[N3], _4: Tag[N4], _5: Tag[N5], _6: Tag[N6], _7: Tag[N7], _8: Tag[N8], _9: Tag[N9]) extends Tag[Digit9[N1, N2, N3, N4, N5, N6, N7, N8, N9]] with NatTag