When the company planted our maple,I thought it was too far up; we'd never get it to grow sitting way up like that....it is doing great!

If the hole is filled with water, I would suggest that your water table is very high...or that the tree is planted in a low spot (and water drains to it )...or that there is a hardpan a few inches below the root ball and the water cannot drain...or you are over irrigating. Planting too deeply is a very common issue, but water should NOT be in the planting hole, regardless. The usual rule for planting in clay soils is to plant high. Don't amend.

Clay soil does not need to be amended, in most cases. Do you have that famous hard, red Georgia clay? Which is among the best agricultural soil in the nation? Without amendments of any kind? I ask this because I, too, am now living in an area with heavy red clay. I am ceaslessly amazed at the way plants of all kinds thrive. One must simply plant properly, water conservatively....and stand back.

I'll attach a planting guide for you to review, along with the comments I've made above. From my experience, water at the bottom of the planting hole typically means poor drainage for one reason or another. Solve that problem.

Here is a link that might be useful: Planting Guide