According to some blog post a few hours ago it was released just today so my guess they have stock, but when I check it on shop.bitmain.com I don't find the s9 Hydro Miner so I think their priority is to distribute it first to nearby customers before they distribute it globally.
Just in case you receive the miner you can follow the installation guide from here
https://pastebin.com/FsrEjfNa I just translated it already from Chinese, but you can find the real source including the image from here
https://cnforum.bitmain.com/bbs/topics/3380Translated from Chinese:
Ant Mining Machine S9 Hydro Set
This product includes S9 Hydro, water-cooled components, APW5 power supply delivery time: 7 days after confirmation of payment
7450 Chinese Yuan ~ USD$1080.00
18 TH/S
1728W+/-10%
96J/TH+/-10%
11.60-13.00v
360mm x 125mm x 190mm
This is I think the answer to other home miners who looking for the solution to solve the problems of noise and heat dissipation.