I agree and disagree, yes, itis a best practice to only re-pot right after dormancy, however, I do believe it is possible to re-pot with a minimum of stress at other times during the year. Case in point is every single flytrap petflytrap sends out, whether it is potted or a plug, it has been 're-planted' at a non-optimum time, it is simply unavoidable in any respectably sized operation, and look at the quality you get?
Yes, re-potting will stress out your plants, and I am not so sure that the reason you don't see the stress right after dormancy, is there isn't much to stress out. (Good enough reason to do it then right?)
So, my suggestion is if you can wait, please do wait until right after dormancy, if you can not however wait, then be careful, do not disturb the roots, maybe go so far as to cut the pot away from the root ball, and don't disturb the roots or the soil around them when re-planting.
It won't hurt your plant to be root bound for a season, remember, flytraps use their roots primarily as an anchor, and for water, everything else's entry point into the system is the traps and leaves. (yes, roots do absorb some nutrients and chemicals, but you know what I am saying.)
Hope that helps.