In Act III Scene III Hamlet has the opportunity to kill his traitorous Uncle as he prays. The problem is, his Uncle is praying.
"A villain kills my father, and for that
I, his sole son, do this same villain send
Why, this is, not revenge" Act III Scene III Lines 76-79
Hamlet doesn't wish his traitorous Uncle to go to heaven, rather in lines 93-95
"Then trip him that his heels may kick at heaven,
And that his soul may be damn'd and black
As hell, whereto it goes."
He wishes that his Uncle's soul should go to hell.