We know that any number is divisible by 9 if sum of the digits of the number is divisible by 9 . Now sum of the digits from 0 to 9 =0+1+2+3+4+5+6+7+8+9=45 Hence to form 8 digits numbers which are divisible by 9 , a pair of digits either 0 and 9,1 and 8,2 and 7,3 and 6 or 4 and 5 are not used. 
Hence total number of 8 digits numbers which are divisible by 9 =8×(7!)+7×(7!)+7×(7!)+7×(7!)+7×(7!)=36×(7!)