Android executable doesn't run on an arm9 processor board

Question

I created a sample Android executable using an Android.mk file and the ndk-build command. It runs successfully on an arm8 processor board. It doesn't run on an arm9 processor board. Why?

#include <stdio.h>

int main()
{
printf("Hai\n");
return 0;
}

Android.mk consist the following commands

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := Test

LOCAL_SRC_FILES := Test.c

include $(BUILD_EXECUTABLE)