Q: Can I share in-app purchases in family sharing with ios9?

No, What types of content can I share with Family Sharing? - Apple Support :

What you can't share

• Songs added to iTunes Match from outside the iTunes Store.
• Individual Apple Music memberships and other subscriptions, such as magazines and newspapers.
• In-App purchases.
• Items that are no longer available on the iTunes Store.
• Items that you or another member of your family group has hidden. Learn more about hidden purchases.
• Some apps from the App Store. Find out if your app is shareable.
• Ringtones.