I'd boot it with a folded dollar bill, to keep the tube from popping through if the cut enlarges. Then pump it up and see if it's bulged at all in the morning. No bulging -- go ride it, just around town the first ride. I used a cut down Park Tool boot as a permanent fix, and it cut or wore through my inner tube after a half dozen rides. (Park says their boots are for temporary fix only.)

Most cuts that big will bulge, but it depends on how much of the casing threads have been cut.

Shoe Goo has helped to fill a cut, but I normally don't have any around. I've tried crazy glue, but that pops off after one ride.