That is a entry level APU that is not going to give you high fps in modern pc games. 40-60 fps is about what to expect at low graphics.
"With a base clock of 3.0 GHz and a boost up to 3.6 GHz, the A9-9420 offers decent enough performance for basic office applications and light web browsing. However, anything heavier than casual use will overwhelm the CPU."
"Using Cinebench R15 to analyze CPU performance, we see that single core operation is good and relatively good compared to other low-cost options. Indeed, single-core applications run at a decent clip and are reasonably responsive, considering the price. However, multi-core tasks are too much for the dual-core chip. Even low-tiered CPUs from Intel, like the Pentium N3540, best the A9-9420. This is mainly due to the lack of any kind of multithreading; the A9 is limited to two threads, which becomes a major hindrance. "
Even though my CPU isn't amazing it should still be able to run league of legends without any problems at all.
Several tests on www.canyourunit.com tells me that I have a recommended set-up for the games I play, I am pretty sure recommended does not mean 40-60 fps on the lowest graphics.