Hi, 

There are a couple non-native species of Maples whose foliage aren't the classic maple shape (like Acer carpinifolium, but it doesn't appear to be that one) Is there a reason why you are leaning towards a non-native maple (as opposed to any other species with opposite leaves)?

The foliage alone can sometimes not be a reliable trait for identifying plants, but since this plant may be years away from flowering/fruiting, the other option is to try leaf and twig bud characteristics. You could try using the VA Tech dendrology key but if it's an uncommon species it might not be in their database. 

Try following leads for Acer tataricum. The young leaves could not have any lobes yet and why it may be tricky to tell at this stage. Oregon State has some good ID pictures of the buds and leaves. 

If you think its an undesirable species to keep being that it could be invasive or you were hoping for a native plant, you can always compost it and go with something else!

Emily