Why not adalah?
Surely "There is eleven players here" should be accepted!?
"Here are eleven players" should be correct or not?
I think it has the same meaning, just different placement. Your sentence could literally translated as 'Di sini ada sebelas pemain'. But, the placement sometimes can indicate the emphasize of the word in the sentence, isn't it?
Football, my favorite sport, although I usually only play Futsal.
There's eleven players here.
Database omission. Is and are = the same. "There is" should be accepted.