Sort lists by computable values

x={1,2,Style[3,Blue],Style[4,Red],Magnify[5,2],Style[6,Smaller],7,Style[8,Tiny],Style[9,Medium]}

ComputableForm[x_]:=Block[{Style=#1&,Magnify=#1&},x]

Sort[x]

Sort[x,If[Head@#==Style,#[[1]],#]&]

SortBy[x,ComputableForm]