The AGS-W09 has a Kirin 659 chipset and a locked bootloader. Huawei stopped providing unlock codes in 2018. Without an unlocked bootloader, you cannot install any custom ROM. If your tablet is already unlocked (rare), read on. If not, custom ROMs are effectively impossible for this model.
Some very old units (pre-2018) might have been unlocked with a code from Huawei (now discontinued). No working exploit exists for newer firmware. huawei mediapad t3 10 ags-w09 custom rom
No custom ROM is perfect. Here is the reality for the ags-w09: The AGS-W09 has a Kirin 659 chipset and a locked bootloader
Finding a custom ROM for the Huawei MediaPad T3 10 (AGS-W09) read on. If not