If yes can I clean install with 10 iso or do I need to upgrade, and also is there still even a way to free upgrade?
Upgrading, not from 8.0, only from 8.1. But if this is the system with the 8.0 bios oem: dm key from that other thread you can do a direct clean 10 install and the setup will readout and use the oem: dm bioskey.
Just regarding some Windows Tablets to upgrade to Windows 10 Pro. I've 2 Windows Tablets, which origin came with Windows 8.1 Bing Edition/Home, a 8" and a 10.1", both CSC Wisebooks. They're available in Thailand only AFAIK! OK, I was trying to upgrade to Windows 10 Pro and that would works, except for the Touch Screen. We tried a lot of different ways, none was working! So I'm still on running both now on Windows 10 Home, with no any problems, just didn't get the full advantage of Windows 10 Pro! This is just a reminder for those User's, who using a Windows Tablet, to be caution with Upgrades to Windows 10 Pro.