The basic toolbar location can be controlled via the toolbar_location property of plots (e.g. you can pass toolbar_location="above" to your figure). But IIRC that will not center the toolbar, and I don’t recall whether if will be above the title or alongside it. These details as well as size, etc do not currently have any user-facing configuration options.
Edit: this is what a top toolbar looks like:
I am afraid there are not any options to get anything different than that.