The skills developed on 9x9 are VERY applicable to a real game. I have been playing for 3 years and I still study life/death and endgame. I played only 9x9 until I reached 18 kyu on OGS. And then from 18kyu ask the way to 12 Kyu, I dominated in the corners but I had to learn the big board concepts during that time. Nothing wrong with doing it this way.
The skills developed on 9x9 are VERY applicable to a real game. I have been playing for 3 years and I still study life/death and endgame. I played only 9x9 until I reached 18 kyu on OGS. And then from 18kyu ask the way to 12 Kyu, I dominated in the corners but I had to learn the big board concepts during that time. Nothing wrong with doing it this way.