You can talk about "authorship" in relation to a composer, but it nearly always refers to attribution: as in "Beethoven's authorship of work X has been questioned. It's not commonly used to refer to the act or process of composing in general. It is unusual and generally to refer to a composer as an "author" in English. For "authorship" in the context you describe, it will depend on how you phrase it, but "composition(s)" and "work(s)" are your main options.

"Author" and its derivatives are mostly confined to writing in English. An "authored/authorial" CD definitely doesn't work. You would have to say something like "A CD of his works/compositions" or "entirely devoted to his work", or something like that.

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Note added at 17 mins (2012-11-23 20:14:48 GMT)
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Sorry about the double "generally"!

And in the third line I meant to say "unusual and generally unnatural, or even confusing".

In paragraph 2 I meant that these words in English ("author" etc.) are mostly used only when referring to writers.

This question arises in relation to the visual arts too. In Spanish, it is very common to refer to a visual artist as an "autor", but it usually doesn't work well in English.

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Note added at 1 hr (2012-11-23 21:20:51 GMT)
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The one way you might find "authorial" used in relation to music is when referring to details in the score; to say that the accidentals, or dynamics, or metronome markings, for example, are "authorial" would mean that they were put there by the composer rather than an editor. I can't think of another way it might be used when talking about music. So it's rather like "authorship": its use is confined to questions of whether or not something can be attributed to the composer in question. These are very limited special cases.

As for "authored", you might find someone writing that a work was "authored" by a composer, but it's forced and rather unnatural, and there are better alternatives: composed or written. Indeed, "write" is a verb you can often use.