CONFIG_CPU_ARM9TDMI is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Support ARM9TDMI processor

modulename: proc-arm9tdmi.ko

configname: CONFIG_CPU_ARM9TDMI

Linux Kernel Configuration
└─>Support ARM9TDMI processor
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
A 32-bit RISC microprocessor based on the ARM9 processor core
which has no memory control unit and cache.

Say Y if you want support for the ARM9TDMI processor.
Otherwise, say N.

source code: