It is very clear that the order allows it (but that doesn't mean that's what is being enforced; as with the Muslim ban, it's quite possible that on top of whatever disputes there are about the policy in the text, the enforcement, especially initially, may not align with the text). In relevant part, and note the conditions are βandβ conditions:
Sec. 3. Scope of Suspension and Limitation on Entry. (a) The suspension and limitation on entry pursuant to section 2 of this proclamation shall apply only to any alien who:
(i) is outside the United States on the effective date of this proclamation;
(ii) does not have a nonimmigrant visa that is valid on the effective date of this proclamation; and
(iii) does not have an official travel document other than a visa (such as a transportation letter, an appropriate boarding foil, or an advance parole document) that is valid on the effective date of this proclamation or issued on any date thereafter that permits him or her to travel to the United States and seek entry or admission.
If you have a visa, you don't need a separate travel document; the order exempts both people with current visas and people with current nonvisa travel documents.
Sec. 3. Scope of Suspension and Limitation on Entry. (a) The suspension and limitation on entry pursuant to section 2 of this proclamation shall apply only to any alien who:
(i) is outside the United States on the effective date of this proclamation;
(ii) does not have a nonimmigrant visa that is valid on the effective date of this proclamation; and
(iii) does not have an official travel document other than a visa (such as a transportation letter, an appropriate boarding foil, or an advance parole document) that is valid on the effective date of this proclamation or issued on any date thereafter that permits him or her to travel to the United States and seek entry or admission.