Version 9.00 was not merely a stability patch; it introduced visible changes to the PS4 operating system. Key features included:
There are two versions of the 9.00 firmware. Ensure you download the one that matches your needs from a trusted archive like Softpedia or the Internet Archive : ps4 900 firmware download install
The PS4 requires a very specific folder structure to recognize the update file. Connect your USB drive to your computer. Open the drive and create a folder named (all caps). Version 9