How do you CREATE TABLE AS SELECT (CTAS) with a composite type?
I don't think you can do it the way you are trying to... if my understanding of "A pseudo-type cannot be used as a column data type" is correct.

However, you can do something similar. 

First, you define your composite type (for instance, we have a "point in two dimensions", with fields x and y):

-- Need to define the composite type
CREATE TYPE point_2d AS
(
    x real,
    y real
) ;


Then, you can write 'literals' that need to be cast to point_2d so that PostgreSQL know which exact type they have. So, this works:

CREATE TABLE 
    ttt AS
SELECT
    *
FROM 
(
    VALUES 
    ('(1.5, 2.5)'::point_2d, '(-1.3, -2.2)'::point_2d),
    ('(2.3, 4.4)'::point_2d, '(-2.2, -3.3)'::point_2d)
) AS lines (start_point, end_point) ; 


And then, you can perform queries like:

SELECT
    (start_point).x AS x_start,
    (start_point).y AS y_start,
    (end_point).x AS x_end,
    (end_point).y AS y_end
FROM
    ttt ;