I'm looking for a good Minecraft Hackclient to test my anticheat on my server. He should also be free and version 1.8.9
LiquidBounce is currently the best free client: https://liquidbounce.net/
There are better clients, but unfortunately they cost money.
I program one myself and could test it on your server.
Adde times SimplyBlack # 8202 on Discord.