Can't really see much from your image, but I'll comment on a few cultural things. Osmanthus fragrans doesn't fare well in the heat unless it has some protection from the sun during the hottest part of the day. They also need reasonably good drainage, and plenty of nice, cool mulch over the root system (not on the trunk).

I hate to see you think too much about fertilization this late in the growing season, but if you haven't fertilized at ALL, then a light dose of a soluble all purpose product won't hurt. Just don't use a slow release at this time of year.

If this plant were mine, I would prune it back heavily in the very early spring, in hopes that it will fill back out. But if you are growing it in full sun, it is not likely to perform well for you.

Scale insects can be an issue, so I suggest you inspect your plant for signs of this problem.

Here is a link that might be useful: Tea Olive fact sheet

I notice that it's next to a brick wall. That could be reflecting an extra amount of heat back onto it. It might be too close to the wall too. In Zone 8, I think it's going to need some shade, at least during the hottest part of the day. I think I would cut it back too. It's slow growing, so if you didn't want to cut it all back, you could prune the outer branched "trunks" and leave the inner ones.

It's really hard to judge what the best thing would be in your situation. I think if it were mine, I would cut it back and move it to a shadier spot if I could. I would at least try to move it more away from the wall. Wait until Fall when the temperature have dropped.