I can't find a direct interactive way to sort a tabulate report. However, it acknowledges the value ordering column property.
This code should work to conditionally set value ordering for a column (only tried it in JMP 10):
dt = Open( "$SAMPLE_DATA/Car Poll.jmp" );
col_list = {:size, :age};
Summarize( g = by( col_list[1] ), m = Mean( col_list[2] ) );
col_list[1] << Set Property( "Value Ordering", Eval( g[Rank Index( m )] ) );
dt << Tabulate(
Add Table(
Column Table( Analysis Columns( col_list[2] ), Statistics( Mean ) ),
Row Table( Grouping Columns( col_list[1] ) )
)
);