Hi TorontoJoe,
Here in my zone7, I now, let the suckers grow one year more, and remove them then.
By then, you can shape them as you want, as the trunk is thicker.
For that one, I would probably hesitate on two solutions:
Solution1 : do nothing . Let her grow.
Solution2 : Bend the trunk like for an espalier. Keep the bottom half straight, and top half bent to the side - you can achieve that with some stacking ... but the tree will take more space ...
By bending the trunk, you should trigger some lower buds to start growing.
If you want the tree to grow, don't forget to fertilize.
The problem if you cut the trunk now, is that moisture will escape the plant from the wound and if the tree is just adapting, it could mean killing her ...
The choice is yours ...
For the roots, sun hitting the plastic may cook them ... You are the judge, but I probably would be putting the jar in a dark pot to avoid that cooking.
Of course, if the sun is just heating to the liking of the tree, letting her like that is best ... Depends on your setup.
For now, at least, monitor the temps to detect any rising on the heat behind your window...
Good luck !