K@(Subscript[9, 27])

Module[{i=9,j=27,l=T@(Subscript[9, 27])},(Subscript[S, Reverse@Join[Reverse@l[[1]],l[[2]]]->"1"])@(Subscript[S, Reverse@Join[Reverse@l[[3]],l[[4]]]->"2"])@K@(Subscript[i, j])]

?MonomialQ

?MatchQ

Table[MatchQ[(t^p), 1|(t^(_.))], {p,Range[-2,2]}]

?_.

{7+(t^3), t} /. c_.+(t^(p_.)) :> {c,p}

?___