MIUI 9 Global Beta ROM and China Developer ROM are rolling out for the first batch of devices.
However, Xiaomi has released MIUI 9 China Developer ROM for 13 devices. All ROMs come as Fastboot ROM.
If you want to try MIUI 9 China Developer ROM while waiting for the Global Beta ROM then you have to flash the ROM using the Fastboot method.
Note: Flash this ROM on your own risk. This Developer Beta ROM which may have unexpected bugs.
Download MIUI 9 China Developer ROM for 13 devices:
Mi MIX (2056M)
http://bigota.d.miui.com/7.8.17/lithium_images_7.8.17_20170817.0000.00_7.0_cn_9990b49720.tgz
Mi Note 2 (2095M)
http://bigota.d.miui.com/7.8.17/scorpio_images_7.8.17_20170817.0000.00_7.0_cn_6bbd1ed7bf.tgz
Mi 5 (2056M)
http://bigota.d.miui.com/7.8.17/gemini_images_7.8.17_20170817.0000.00_7.0_cn_642d70cc03.tgz
Mi 5s（2059M）
http://bigota.d.miui.com/7.8.17/capricorn_images_7.8.17_20170817.0000.00_7.0_cn_57eb269d28.tgz
Mi 5s Plus （2088M）
http://bigota.d.miui.com/7.8.17/natrium_images_7.8.17_20170817.0000.00_7.0_cn_5e16a63a14.tgz
Mi 5c （1836M）
http://bigota.d.miui.com/7.8.17/meri_images_7.8.17_20170817.0000.00_7.1_cn_ce9d9f0bc3.tgz
Mi Max 2 （2125M）
http://bigota.d.miui.com/7.8.17/oxygen_images_7.8.17_20170817.0000.00_7.1_cn_4e886698e1.tgz
Mi Max （1927M）
http://bigota.d.miui.com/7.8.17/hydrogen_images_7.8.17_20170817.0000.00_7.0_cn_0cce280110.tgz
Mi Max Prime （1954M）
http://bigota.d.miui.com/7.8.17/helium_images_7.8.17_20170817.0000.00_7.0_cn_634284f8ae.tgz
Mi 4S （1344M）
http://bigota.d.miui.com/7.8.17/aqua_images_7.8.17_20170817.0000.00_7.0_cn_dbe7543620.tgz
Mi 4c （1361M）
http://bigota.d.miui.com/7.8.17/libra_images_7.8.17_20170817.0000.00_7.0_cn_5d129ccbe3.tgz
Mi Note Pro （1480M）
http://bigota.d.miui.com/7.8.17/leo_images_7.8.17_20170817.0000.00_7.0_cn_49fd98b988.tgz
Redmi 4X （2113M）
http://bigota.d.miui.com/7.8.17/santoni_images_7.8.17_20170817.0000.00_7.1_cn_3d2774fe54.tgz
