I have Umb 8 & Vendr working nicely. This morning, I have needed to create a node in the root of the website programmatically so create a method in my ApplicationComponent like this:

private void CreateSettingsSection()
    {
        using (var ctx = _umbracoContextFactory.EnsureUmbracoContext())
        {
            var settingsNode = ctx.UmbracoContext.Content.GetAtRoot().FirstOrDefault(x => x.IsDocumentType(Settings.ModelTypeAlias));
            if (settingsNode == null)
            {
                var node = _contentService.Create("Settings", -1, Settings.ModelTypeAlias);
                var result = _contentService.SaveAndPublish(node);
            }
        }
    }

but the code fails to run due to a Vendr licensing issue (we dont have a license bought as yet, but I'm running it on localhost).