first , yes a single S9 will be able to try all the 2^32 Nonce for about 3000 suggested blocs in one second, but most probably none of these blocks will have a hash output that starts with the defined famous numbers of leading zeros, even though you tried all 2^32 variations for each of the 3000 suggested blocks, so the miner would probably go back and put together a different set of transactions in a new suggested block, hash that block and then iterate thru all possible Nonce for that block and so on, notice 2 things here:
1) there are a decent amount of unconfirmed transactions in a memory pool, and even thu only an average of 6 is added a second the number of variations in both order and size(number of included transaction) is humongous.
2) part of the Message to be hashed is a especial transaction that will reward the miner with his 12.5(for now) bitcoin to his wallet(called coin base transaction), which makes the hashing trial for that miner unique than other miners! this is GENIUS...
it will make what works for one miner not working for the others, distributing the possibility of solving block even more.
so in other words, the race is not only to find a Nonce for a certain suggested block, it's more about arranging a suggested block, with all of it's ordering, length, time stamp...and coinbase transaction, such that there is a Nonce for it that will make it's hash meet the difficulty needed, only a rare percentage of these block would actually have the ability to give you leading zeros when hashed!
reading more now on to actually obtain the unconfirmed transactions and the broadcast of a solution,
just LOVE IT
any references to find information about that?!
thanks again
