Get Earth Engine Object Type

The answer is dangerously close to your non-solution, but the type of object you're dealing with is ee.ComputedObject. The solution to your issue in this case is to cast to ee.Geometry.

var polygon = ee.Geometry.Point([0,51.477]).buffer(10000); // a circle in London    
var random_points = ee.FeatureCollection.randomPoints(polygon.bounds(), 100); // 100 random points in London
var point_list = random_points.geometry().geometries();
print(point_list); // prints -- List (100 elements)
var one_point = point_list.get(10); // The 11th point.
print(one_point); // prints -- Point (-0.03, 51,52)
var small_circle = ee.Geometry(one_point).buffer(100);

print(one_point instanceof ee.ComputedObject) // true