The expression $\frac{9}{\sqrt{2}}$ can be simplified by rationalizing the denominator. To rationalize, we multiply both the numerator and the denominator by $\sqrt{2}$:

$\frac{9}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = \frac{9\sqrt{2}}{2}$

So, the simplified form of $\frac{9}{\sqrt{2}}$ is:

$\frac{9\sqrt{2}}{2}$

Would you like further explanation or another calculation? Here are some related questions:

1. What is the rationalization process used in this problem?
2. How do you handle square roots in a fraction when simplifying expressions?
3. How do you convert the simplified expression back to a decimal?
4. What happens if we multiply both the numerator and denominator by a different square root (e.g., $\sqrt{3}$)?
5. What is the importance of rationalizing the denominator in mathematics?

Tip: Rationalizing the denominator helps in simplifying expressions and can make working with fractions easier in further calculations.