Both are possible, for the verb can be used in both senses, and here it is not entirely unequivocal (like, e.g., in Mark 3:14, where it is unequivocally "appointed" and not "created, or in Gen. 1 where it is unequivocally "created" and not "appointed"). The Vulgate preserves this equivocation by "fecit", which also can mean both actions.
Probably the "appointed" is more plausible, for Paul refers to Jesus not as a creature, saying elsewhere that the Father brought into existence the entirety of creation through Him (Hebrews 1:2), thus excluding Him from this entirety. And here in the immediate sequence Jesus' glory is counterposed to the glory of Moses as that of Maker to the made, a house builder to a house, the verb κατασκευαζω applying both to Jesus and God, and the "house" is referred to Moses, as a part of this house and acting in it as a servant, and also all humans, including Paul himself (ου οικος εσμεν εμεις), but Jesus together with God is outwith the "house", a.k.a. creation, expressed by the prefix ἐπὶ which with accusative οικον means "onto", i.e. "upper surface of", as in "got up onto the horse", thus not a part of the surface of the horse, in this instance, not part of the creation.
However, "created" is also plausible, for Jesus is created in His human nature and in His human nature remained faithful to God, always performing things pleasing to Him (cf. John 8:29), and having lived a life of utter obedience, up to the death on cross (Phil. 2:8). Some ancient translations, thus, e.g. a Georgian canonical translation of 11th century make this option, putting "created" unequivocally.