I have hundreds of computers for mining , I really need to have an official mining pool to control all of them.
You're welcome to create worker accounts on zec.suprnova.cc for all of them
I need to create one user account or one account for each computer?
you can create one user account, then separate worker names and passwords for each machine
There won't be any 'official pool', Zcash company is not obligated to run any pool.
It doesn't really matter since every connection is handled separately. You can create a worker for every physical computer to maybe monitor them better but it is not obligatory
can it be fully anonymous for me？
Sure, just set the checkmark on "Anonymous account" on "My Account"
Here comes the 'I have access to 100s of computers because I work in IT for a company or school and I bet no one will notice an extra $5000 power bill but then they do and I'l fired or expelled'