Toddler sleep help

Any advice for an 18 month who has a hard time going to sleep at night?

Her bed time is already later than what I would like (9:30) and usually she falls asleep great. Lately she has been taking an hour or so to fall asleep at night. We don’t let her nap past 4 I’ve found that makes it difficult at night. She only takes one nap! She usually wakes up anywhere between 8:00-9:00 in the morning.

Is it a growth spurt? Am I already going to have to drop her only nap? :(