Short answer
HubSpot's KB: confirm the HubSpot Integration package is on 3.0.1 in Installed Packages. An Insufficient Privileges error means the installing user needs Download AppExchange Packages. The legacy Visualforce module is being deprecated.
1. In HubSpot
The relevant screen in my demo portal.

2. Worth knowing
Unused HubSpot Intelligence records can be deleted after upgrading.
3. Related
Salesforce sync rules and sync errors.