Hi Oguzhan,
I suggest you use SPI in communicating AD9912 with Raspberry Pi, or Adruino since I think it would be easier to wire them as compared when using parallel. I'm not much of an Arduino user so I can only recommend library for Raspberry Pi. For C/C++ library you can use the bcm2835 library by Mike McCauley. The instructions on installing and using the library is already within that website. I have tried using this at Raspbian OS, and it works as for SPI functionality. You can also easily use I2C and GPIO's using this library.
Best Regards
Louijie