It is usually Ok to transplant any time if you don't cut or break too many roots.
Not sure what you will find when you move the tree, depends how long ago it was repotted and conditions since then.
Even if it has new roots and the new soil drops off that won't hurt the tree. Transplant gently and refill around the roots gently so as to not break too many of the new roots and it should be OK.
Not even necessary to cut the container. Place fingers over the soil around the trunk, turn the whole thing upside down and gently remove the pot whole. Some soil is sure to fall off but that doesn't matter to the tree. As you turn the tree back right side up more soil will probably fall off - again no problem provided most of the roots stay.
I would avoid using chopstick when filling new soil. Just press it gently in place with fingers to avoid damaging any new roots then water the soil and it should move into any spaces left.