My two cents - it depends. Firstly, on who told you, ie what are their qualifications in the peds PT/orthopedic arena, and secondly, on how bad the problem is.
You see, I have a daughter who has been wearing ankle-foot orthotics since preschool (now 12) for some decently serious ankle weakness problems. She would never have had the support to be able to stand correctly and walk correctly, much less run without them, and by this point in her development, her posture/gait would have been seriously screwed up without them. I go to a peds therapy center to do exercises and stuff on a regular basis with a PT, along with the heavy-duty braces, as well as have her barefoot as much as possible while still maintaining the support as she grows. They have helped tremendously.
I know the MDA demonizes orthotics and shoes and all, and mostly for cause I believe, but there are situations where stuff like this is a right thing to do.
Anyway, I have been around a bit in this department, and there are several things you don't want to do. They would be: take advice from someone not qualified in this field; ignore advice from someone who is qualified and experienced; go cheap on the orthotics if they are needed (meaning stay away from off-the-shelf stuff... Custom is more expensive, but also works better and is hugely more comfortable); and assume this will be forever.
My daughter will be done with the heavy duty stuff about 18 months after menarche, because that is when her bone growth will be done, and then transition into custom inserts. After/concurrent to that, I will see if Vibrams and Co. might be right, along with the barefooting we already do. Watching kids walk horribly is kinda a pet peeve of mine, just from my experiences with the daughter.
Not being a peds orthopedic specialist, I cannot really tell you yea or nay, but I would advise you to take this earnestly and seek out good advice, and then take it. (Not that you aren't - just sayin'). All children's hospitals have peds orthopedists who can give you the entire lowdown in one visit, just as a resource, if you haven't got good people. In my experience, the peds orthopedists are interested in getting the kids out of inserts/braces just as much as they are interested in getting them into them, once the problem is helped.
I have a mantra that I have spouted for years... "If I eat right, I feel right. If I feel right, I exercise right. If I exercise right, I think right. If I think right, I eat right..." Phil-SC