A 9 month old is not old enough to be crying it out. They cry because they need something. They are hungry or lonely or something. Your baby needs you to take care of her.
Your baby is still learning to trust or mistrust you. If she is hungry and crying and you do not come she is not going to build that trust she needs to have a healthy relationship.
I think crying it out is a sad way to parent a child especially a baby. Allowing a few minutes of fussing is not a harmful thing to do but allowing a baby to cry an extended amount of time, enough to wake others in the household is too extreme to me.
If you can't take care of her needs during the night then continue to allow her to sleep in the pack-n-play until she is older.
She will have growth spurts every couple of months, she is going to triple her birth size over the 1st 2 years of her life. She is going to be hungry during these times, if it's hot outside she may wake up thirsty, etc....she may just have a bad dream and be scared.
She needs you to figure out what is going on. I always kept the kids on a pretty stable schedule for meals. They got breakfast, a snack, lunch, a snack after nap time, dinner, and a good size snack late at night, about 8:30, right before bed. They usually slept all night when they were not hungry. But they still had times whey they woke up starving. The body uses a lot of energy during the sleep cycle because it is fighting off infections, fixing cellular damage, processing lots of bodily functions.