Yes, your light is too big for the area, and it will be almost impossible to CONTROL the environment in your area. 86F is high, and its at the VERY high point. You can control the temps a bit by as already mentioned, removing the ballast out of your space. Another thing you might consider is the 25ft of ducting. I would imagine it is the flexible stuff. If you can reduce the length to half or less than that, I think you would gain extra horsepower out of your fan(s) resulting in some lower temps. If you can replace the flexible to whats called 'warm air pipe', using as little bends as possible ....that would be much better. The best you will be able to do is about 10F above the ambient temperatures being pulled in. That means if you're pulling in fresh air at 75F, then you should expect about 85F in your grow space.

SN