David's Tabernacle - Amos 9:11,12

AMOS 9:11,12
11 In that day [not necessarily, in that very day, but, after that] will I raise up the tabernacle of David that is fallen, and close up the breaches thereof; and I will raise up his ruins, and I will build it as in the days of old [there is no mention of either the northern or southern kingdom - the emphasis is specifically on the restoration of David's tabernacle]:
12 That they may possess the remnant of Edom, and of all the heathen, which are called by my name [even the Gentiles would be called by His name], saith the LORD that doeth this [this remarkable thing would be done by the Lord].

The dispensational view is that during the Millenium, David will literally reign over Israel, and the Gentiles will receive a measure of benefit from that. But let's see how the Apostles applied it:

ACTS 15:16,17
16 After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up:
17 That the residue of men might seek after the Lord, and all the Gentiles, upon whom my name is called, saith the Lord, who doeth all these things.

The Apostles used this verse as their basis for conceding that Gentile believers in Jesus could enjoy all of God's covenant blessings without becoming Jewish proselytes, even without a literal reign of David in Israel.

David's throne was the Lord's throne. ("Solomon sat upon the throne of the Lord".) So when the Bible said David shall reign over them, it probably meant Jesus shall reign over them - for Jesus is the seed of David. When Amos said God would restore David's tabernacle, it was fulfilled in a greater way than by the mere return to the land of Israel of David's family-line after the captivity, because more families than only David's returned to the land. It was probably fulfilled by the coming of Jesus, who is the seed of David, and who reigns in heaven, and by whom the Gentiles now call upon the Name of the Lord and are themselves called by His Name.

The Apostles saw Amos' prophecy as a basis for the presentday inclusion of Gentiles in the blessings of the New Covenant. There doesn't appear to be any specific New Testament teaching which implies the Apostles might have been expecting some future dispensational fulfillment of Amos' prophecy.

David's descendants were restored to the land after the captivity. David's seed - the Messiah, Jesus - has come. The remnant has obtained what was promised - and the Gentiles are grafted-in. The prophecy is being fulfilled now. That seems to be how the Apostles understood it.

Maybe there shall be greater outworkings of the prophecy in future: it is not for us to know the times and seasons which the Father has placed in His own hands. But what we do know about this prophecy, based on Apostolic authority, is that Jewishness or Gentileness is of no avail [for it's neither the northern nor southern kingdom that was to be God's focus at the time of restoration, but David's tabernacle, i.e., those belonging to God's covenant of mercy through Jesus Christ]. What avails is a new creature. Amos foresaw this.