Let for the \( 9^{\text{th}} \) term in the binomial expansion of \( (3+6x)^{n} \), in the increasing powers of \( 6x \), to be the greatest for \( x=\dfrac{3}{2} \), the least value of \( n \) is \( n_{0} \). If \( k \) is the ratio of the coefficient of \( x^{6} \) to the coefficient of \( x^{3} \), then \( k+n_{0} \) is equal to:
