From a religious:
When the motu proprio came out in 2007, it gave permission for clerics to use the older breviary to fulfill their obligation. I belong to the OCDS and many of our members wondered if we could pray the older form of the breviary to fulfill our obligation (Morning and Evening Prayer). We inquired with the provincial delegate but he didn’t seem to understand the motu proprio and couldn’t give a clear answer. What do you think?
As you mentioned:
SP Art. 9 § 3. It is lawful for clerics in holy orders to use even the Roman Breviary promulgated by Blessed John XXIII in 1962.
There is nothing ambiguous about that. If you are a cleric, and you use the older form of the Office, you fulfill your obligation. That applies to the Roman Breviary. I suppose it would apply to the Office for religious orders if they have a proper form.
Art. 3 If Communities of Institutes of Consecrated Life and of Societies of Apostolic Life of either pontifical or diocesan right which in conventual celebration or celebration of the “community” in their own oratories desire to have celebration of Holy Mass according to the edition of the Missale Romanum promulgated in 1962, this is licit for them. If an individual community or the whole Institute or Society wants to put into effect such celebrations often or habitually or permanently, the matter is to be determined by the Major Superiors according to the norm of law and the particular laws and statutes.
If this is the case for Mass, why would it not be the case for the Office?
If you want a better answer, you might apply to the Pontifical Commission “Ecclesia Dei”.
Also, I will now invite members of religious orders who may have some experience with this question to sort things out.