9 i/p ADDER (1bit wide) :-

module add9 (cout3,cout2,cout1,s,a,b,c,d,e,f,g,h,i);
input a,b,c,d,e,f,g,h,i;
output cout3,cout2,cout1,s;
add8 ad1 (c3,c2,c1,s1,a,b,c,d,e,f,g,h);
ha h1 (c4,s,s1,i);
ha h2 (c5,cout1,c4,c1);
ha h3 (c6,cout2,c5,c2);
ha h4 (c7,cout3,c6,c3);
endmodule

TEST BENCH :-

module adtb ();
reg a,b,c,d,e,f,g,h,i;
wire cout2,cout1,s;
add9 dut (cout3,cout2,cout1,s,a,b,c,d,e,f,g,h,i);
integer z;
initial
begin
for (z=0;z<=511;z=z+1)
begin
{a,b,c,d,e,f,g,h,i}= z;
#1;
$display(a,b,c,d,e,f,g,h,i,":",cout3,cout2,cout1,s);
end
end
endmodule