Does Cartaro supports clustering?

Cartaro does support clustering and it is shown with about 8000 points on http://demo.cartaro.org/ on the Switzerland map. The clustering can be configured in the map settings (Cluster Features behavoir).

Note however anyone can edit the demo and so the clustering might not be visible at all times until the demo resets.

In addition to augustus' comments:
As an alternative you could do the clustering server-side by either providing an adapted SQL to GeoServer or by applying Rendering Transformations (http://docs.geoserver.org/stable/en/user/styling/sld-extensions/renderin...).
Which way is best for you depends on several factors, e.g.:
* Which browsers must be supported (IE8 won't perform well with client-side clustering)
* Do you need your features on the map only or do you need them as nodes within Drupal

In order to have Drupal nodes the direct way is to go for client-side clustering