Question

Roughly how long will a waxing crescent remain in the sky?

Answer 1

from 9:00 AM to 9:00 PM . the mid-phase standard time is 3pm.

Answer 2

The moon never leaves the sky, no matter what phase it's in.

The waxing crescent phase represents  1/4  of the cycle of phases . . .
roughly a week.

(7.383 days)