9. Fill the $3 \times 3$ grid with the numbers $1,2,3,4,5,6,7,8,9$ randomly, with each small square containing exactly one number, and all numbers being distinct. The probability that the sum of the numbers in each row and each column is odd is $\qquad$.
Answer $\frac{1}{14}$.
To make the sum of numbers in each row and each column odd, it is necessary that each row or each column either has only one odd number or all three are odd. Therefore, the number of ways that satisfy the condition is $C_{3}^{1} \times C_{3}^{1} \times 5! \times 4!$, so the required probability is $\frac{C_{3}^{1} \times C_{3}^{1} \times 5! \times 4!}{9!}=\frac{1}{14}$.