Hi Ricco,
Rev 6:9 And when he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held:
I do not believe that this is literal, but is a point in time before the resurrection of the dead and is saying that all those Elect that are "under the altar" or that sacrificed there lives for Christ, have not yet received their reward.
They were not literally crying out, but God is saying that He has not forgotten them and recognizes that they are still waiting for the resurrection while in their graves.
In Matt. 27 where the Saints (believers in Christ) were resurrected, this is just like Lazarus was raised from the dead. Of course this was back to physical life and they later died and are awaiting the resurrection to real life in the grave.
As for how Samuel appear from the dead?
1Sa 28:11 Then the woman said, "Whom shall I bring up for you?"
And he said, "Bring up Samuel for me."
v. 12 When the woman saw Samuel, she cried out with a loud voice. And the woman spoke to Saul, saying, "Why have you deceived me? For you are Saul!"
v. 13 And the king said to her, "Do not be afraid. What did you see?"
And the woman said to Saul, "I saw a spirit ascending out of the earth."
v. 14 So he said to her, "What is his form?"
And she said, "An old man is coming up, and he is covered with a mantle." And Saul perceived that it was Samuel, and he stooped with his face to the ground and bowed down.
Saul ask for Samuel, so what does the medium see, verse 13 "I saw a spirit," and verse 14 "an old man," but she said it was Samuel. But we know this was not Samuel, but a lying spirit.
1Ki 22:21 Then a spirit came forward and stood before the LORD, saying, 'I will entice him.'
v. 22 And the LORD said to him, 'By what means?' And he said, 'I will go forth, and will be a lying spirit in the mouth of all his prophets.' And he said, 'You are to entice him, and you shall succeed; go forth and do so.'
1Jn 4:1 Beloved, do not believe every spirit, but test the spirits to see whether they are of God; for many false prophets have gone out into the world.
Anyway we know that nobody is in heaven because of what Jesus said.
John 3:13 No one has ascended to heaven but He who came down from heaven, that is, the Son of Man who is in heaven.
mercy, peace and love
Kat