Note: Pin D9 on the Arduino is not the same pin 9 on the ATmega328 IC. Pin 15 on the IC is actually the pin for Digital Pin 9 (D9) on the Arduino. If you want to see the pinout for the ATmega328 IC, ...

which offers a ATmega328 microcontroller with Optiboot (UNO) Bootloader. The Metro 328 has been created to provide extra features on top of what you would expect from the Arduino Uno offering ...