is it possible to hook into pulumi update/create/destroy events and for example make a final backup before destroy?

You mean at the stack update level? Or the resource update level? There are webhooks available in the Pulumi service, which would allow you to be notified of these events at the stack level, and there are APIs (not yet documented - but we can provide guidance) to programmataically get the stack. Inside the program, we don't currently have ways to hook individual resource create/update/delete - this is tracked in https://github.com/pulumi/pulumi/issues/1691. If this looks like what you want - please do add details of your use case there.