Tips for siblings with large age gaps please!

My daughter is 9!!! And we’re pregnant with our son due in a few months. I am so scared that with a 9 year age gap there’s going to be resentment when he’s born. When we first told her I was pregnant, she was upset. She’s been our only baby for so long, so I totally understood. But as I began showing she would rub my belly and talk to the baby. I was so excited she showed any affection towards him. I was so worried she’d be upset the whole pregnancy. But she’s surprisingly positive! I’m just worried with the newborn phase with all the crying and exhaustion, she’ll go back to being upset. Any tips for large age gaps? My only idea right now is one my sister suggested, we get a present from the baby and give it to her when we get back from the hospital. Please drop any ideas below! Thank you!