Facebook Login - iOS 9 - Without Safari

Seems there's no way to get the previous behavior using newests FB SDKs in iOS9+. You can use an old SDK to do that. Here's a response from the facebook to that question:

From now You can change loginBehavior to FBSDKLoginBehaviorSystemAccount, so FBSDKLoginManager gets Facebook logged in user from iOS Facebook Settings ;)

FBSDKLoginManager *fbLogin = [[FBSDKLoginManager alloc] init];
fbLogin.loginBehavior = FBSDKLoginBehaviorSystemAccount;

From FBSDKLoginManager:

Declaration: FBSDKLoginBehaviorSystemAccount
Description: If the account is not available to the app (either not configured by user or as determined by the SDK) this behavior falls back to FBSDKLoginBehaviorNative.
Note: If the account is not available to the app (either not configured by user or as determined by the SDK) this behavior falls back to FBSDKLoginBehaviorNative.