We can simplify the given expression by canceling out the common factors.
First, we can simplify the expression inside the parentheses by dividing every term by 6df^6:
$$\frac{30d^2f^8 - 12d^3f^6 + 6d^2f^9}{6df^6}$$
$$= \frac{5f^2}{d} - 2d + f^3$$
Therefore, the simplified expression is:
$$\frac{30d^2f^8 - 12d^3f^6 + 6d^2f^9}{6df^9d^2} = \frac{5f^2}{d} - \frac{2}{d} + \frac{f^3}{d^2}$$
Answer: $$\frac{5f^2}{d} - \frac{2}{d} + \frac{f^3}{d^2}$$