Overwriting Mac Os 10.4 and replacing with 9.2

I have an old MacBook Pro (Apple MacBook Pro "Core 2 Duo" 2.2 15-Inch (Santa Rosa) features a 2.2 GHz "Core 2 Duo" processor (T7500)) running Mac OS 10.4.

I would like to overwrite Mac Os 10.4 and replacing with 9.2. The system 9 install disc apparently wont let me do that.

I CAN'T install a a 10 that is able to run 9 because this MacBook has an Intel processor (which can't run classic 9 on top of 10)

How do I erase 10 and install 9?

Thanks