I don't think it's something you can grow out of exactly. I do think slow processing it is something you can learn to work with and compensate for so it's less obvious.
I say this about my DD and her LD's.. She is 21 and graduating from college this spring. Her LD's haven't disappeared but she has learned (through hard work) how to function despite her LD's. Knowing exactly what her LS's were helped us to teach her what she needs to do to write that college paper and/or read that text book. That she can't emulate other students and try and bang out an essay not matter how short in a evening.
Why are you anxious to have her processing skills improve on WJC? Those scores help you & her teachers understand where she struggles. My son has low processing & WM and I found was that some grades have been harder than others. Just because things seems better today, might not mean that when the next grade levels up (requires drastically new skills) this may come to play again. Often grades like 4th, 6th or 7th, and 9th are level up times where teachers expect higher levels of EF & drastically more seatwork or homework.