Pennant Hills is super safe, I have lived here for 7 years and never experienced crime. If you want to research yourself check out the local Police Facebook page as they feature crime stats. Spoiler: It's pretty much non-existent here :P
Hello NatalieM4 have you read the suburb reviews on the website? This is what one user had to say about Pennant Hills. The Homely Team
www.homely.com.au/pennant-hills-hornsby-sydney-greater-new-south-wales "I have lived & grown up in the hills area since 1974 and can highly recommend Pennant Hills and surrounding suburbs to all that are thinking of moving to here. I have found the area to be a very safe and enjoyable place to bring up a family. Close to public transport options, retail shopping outlets & most importantly great schools are nearby. Two thumbs UP!"