Can we use "Ich habe gehen" instead of "Ich mussen los"? Is this grammatically correct?
The correct phrase is "Ich muss los" or "ich muss gehen"
There is an old-fashioned use of "haben" in the sense of "to have to". Examples are "Ich habe zu danken" (I am the one who is obliged to give thanks) or "Ich habe zu tun" (I am busy, I got things to do).
But the safer option is to use "müssen".