You have almost the exact same sytem and conditions I have. During the summer my temp regularly gets to 90. I tried a 5200btu AC and it made my temp worse.lol Plants seem to be fine. Haven't had any hermies. I do have to keep them watered more though. I usually hit them with about a cup of water in the morning and then hitem good in the evening. Some strains will do fine with the high heat.
The other issue with the heat and humidity is mold. I have to have the fan on high 24hrs a day when I'm getting the good tight buds.