Do you already have organisms in the hatchery ponds?

If not, then I would wait a little longer and top them off in the fall.

What is the total volume of water you will be drawing from the 1-acre pond?

Drawing some cooler water from the 9' level will allow your 1-acre pond to heat up a little more if you get another bad heat wave. The warmer water holds less dissolved oxygen. I would hate to heat your pond during the hottest time of the year without aeration.

Does your 1-acre pond have a good water source? (Will the water you remove probably be replaced soon?)

Those are the safe questions/answers above. In reality, it will probably make very little difference to your main pond. OTOH, why take a small but significant risk for not much gain if you could do it more safely later?