- He willn't go there tomorrow.
- He won't go there tomortow.
Do people use "willn't" our days?
No, no one uses willn't. Only won't is correct in all major dialects. It's actually a contraction of the earlier woll not, but English changed and will became more standard, though the contraction stayed.
You may find willn't in some older texts, but that would have been a conscious decision by the author to buck the standard usage.
No people don't use 'willn't.
It is either - will not or - won't
The short form of 'will not' is 'won't'