Concept:
BCD stands for Binary Coded Decimal. In BCD, each decimal digit is represented by its 4-bit binary equivalent.
Step 1: Decimal number is:
\[
9
\]
Step 2: Binary equivalent of \(9\) is:
\[
1001
\]
Step 3: Therefore, BCD representation of decimal \(9\) is:
\[
\boxed{1001}
\]