There is almost no benefit from going past story quest #9 (well, Vine is very good once you get strong)... you're also on the last Story Quest for at least a year, maybe forever. If your goal is just to complete the story, then you're pretty much there already.

Sanathlig has a guide which has a section for getting stronger ("leveling guide"). If you're interested in playing this game to get stronger for the sake of getting stronger, give that a read maybe?