To simplify \( 6^9 \div 6^5 \) using the Quotient Rule of Exponents, we subtract the exponents:
\[ 6^9 \div 6^5 = 6^{9-5} = 6^4 \]
Thus, the equivalent form of \( 6^9 \div 6^5 \) is:
\[ 6^4 \]
And since you requested a whole number for the exponent, the answer is:
\[ 4 \]