Sounds like you need to plant it in the ground. Then if you need to overwinter it indoors dig it up after it goes dormant. At that time you can root prune it to make it fit into your pot. Don't forget to prune the top to match the root ball.
"gene"

Short of seeing a picture
are you saying that a 5 gallon bucket cannot cover the whole piece of scion with its roots?

Yeah. The cuttings I received were quite long. Now they've got roots at the very bottom and a smaller number of roots at the top. Nothing else on the length of the cutting that was buried.

They've got 3-4 nice big leaves at the very tip top, which is all of the cutting that was sticking out of the soil while it was rooting.

If I stand the plant upright in a 5 gallon bucket, the top roots are about 4 inches higher that the top of the bucket.

Of course, I should have cut them smaller way back before I struck them, but that's what they sent me and I thought maybe that was the size that roots the best.

I've got some 55 gallon barrels and my son has offered to cut them into planters, but 25 gallons just seems over-kill for a brand newly rooted cutting. Not to mention that I can't move it.

In the ground isn't really an option. I have to be able to move them indoors if it threatens to freeze overnight and they will be indoors for the winter by mid-September.

If I cut these things in half at this point will they survive? The top roots don't seem to be enough to support a tree. I don't want to lose these guys.

Oregonwoodsmoke,
if there are enough roots on scion that are in the soil they should be fine and will continue to grow.
You did mention there are ( not ) a lot of roots exposed up top and if left exposed they eventually will wither away.

Personally if mine this is what i would do and would not cut them in half .
I would have cut them in half when first propagating but dont look back now. ; )
Martin