Is this grammatically correct: It depends if my employers agree or not
Solution 1:
Apparently, from Google Books, this construction is not found much in the past; it appears to have become more acceptable since the 1980s, and this is possibly why it doesn't feel as if it really belonged to the language: Google Books — it depends if. It is found increasingly in the past twenty years.
one-gram of the frequency of "it depends if"
There seems to be no rule, but I must say that, personally, I do not feel this construction with "depend" to be as idiomatic as "it depends on whether". (ref.)