It's not likely that they'll breed in the fall. What causes them to breed is what's called a cooling period, then a rise in temperature... that's why they breed in around February when it starts to come out of winter.
You can simulate this by dropping their temps by 10 degrees or so (in the mid-high 70s) slowly for a week or so. Keep it that temp for a couple weeks. Then slowly raise the temp in the next week or so again back up to 90+. That usually gets them to start breeding. Your female is most likely not ovulating as well. There's a period in the year, usually breeding season (Feb-Aug, Sept.) when the window is for breeding when the female's ovulating. You can actually see this by looking under her belly. If there's a small pink spot in the middle area, she's ovulating. It's hard to see if you don't know what to look for but you can google it and you may find a pic of an ovulating Leo. I think I've seen one.
Anyway, hope that helps. You can't just put them together any time of year and expect to breed. If you miss the window, you'll have to simulate the temperatures.