Installed the ADB driver and check that ADB and Fastboot works. Give some comands to get familar how te device reacts. Go fastboot, back to sistem and so on... The most time I wasted getting ADB running,100% running!!
1. For rooting I used the second "Root_with_Restore_by_Bin4ry" method. (Runme and ready) Then I booted the KFHD9.8 to check that I was ready Rooted.
2. For the 2nd-bootloader + TWRP 126.96.36.199 Kindle Fire HD 8.9 I used the fireflash method. Its the easierst way regarding the v8.4.8 who must replaced before installing the sidload for TWRP. But the fireflash tool just detect this feature by himself and give advices in red warnings to do right. Simple app tool! On Youtube are videos who shows in practice how it works. All is based on the original method from hashcode. By intrest take a look there. He explain the same like fireflash do automaticly. He do it with adb comands and the files are almost the same ( http://forum.xda-developers.com/show....php?t=2128175 ) I guess the fireflash method is almost the best for Super Noooobs like us but look some videos from Youtube to decide to go with adb or fireflash. The tutorial also explain what you have to check on the app! Do so and Your fine.
3. Roms: After that I played a little bit what I have gotten as a rooted device with TWRP and spend a time to flash diferent Roms to see how it works. At last I endet up with a CM11 ROM from Hashcode. Its almost the best! Its a Kitkat who realy works! Go to this thread. His update from 03/15 is amaizing: http://forum.xda-developers.com/show....php?t=2543481 - Must flash!!!!!!
Fear factor: I guess you are scary regarding so many posts from bricked devices. But for shure there is no need. Almost all devices bricked by flashing broken or wrong files for outhers devices then KFHD9.8 e.g. not following the procedures as described and so on... So I only copy what the dev guys just pray so many times: Download the right files and double check, trippel check the MD5 and follow the procedure so strictly as a nob who doesnt know whats going on should do. If done so it works! First aid is good but when You do right there is no need. May be more people with sucessfull transformed KFs should give positiv feedback to confirm that the (Hashcode) method is save!
Send from HW: Kindl HD 8.9 - SW: Android 4.4.2 KitKat < CM 11.0 HC mod.