To rewrite \( 9^{\frac{3}{2}} \) using radical notation, we can follow the laws of exponents which state that \( a^{\frac{m}{n}} = \sqrt[n]{a^m} \).
For the expression \( 9^{\frac{3}{2}} \):
- The base is 9, which can be rewritten as \( 9^{\frac{3}{2}} \).
- This can be expressed as \( \sqrt{9^3} \).
Thus, in radical notation, \( 9^{\frac{3}{2}} \) can be written as:
\[ \sqrt{9^3} \]
So, your final answer is:
\(\sqrt{9^3}\)