Mike,
Heb 9:15 is a bit easier to understand when you know what a kinsman redeemer is. I don’t have it all figured out yet, but the Spirit just put that in my head about a hour ago. I will copy and paste a brief quote concerning kinsman redeemer below. 

The idea of a kinsman- redeemer was established back in the Old Testament. The person who had this role had several obligations:
  * If anyone from poverty was unable to redeem his inheritance, it was the duty of the kinsman to redeem it (Lev 25:25,28; Rth 3:9,12).
  * He was also required to redeem his relation who had sold himself into slavery (Lev 25:48,49).
The Hebrew word for redeem is “goel”. It also had the meaning of revenger, avenger, deliverer and ransom. In the Hebrew culture, the nearest male blood relative could act as a person’s redeemer. Recall in the book of Ruth that Boaz became Ruth’s kinsman- redeemer (Rth 3:9-4:8).
God is the great “goel” of his people. Consider the following passage in which we see all of the salvation and redemption definitions we have covered.
Wherefore say unto the children of Israel, I [ am] the LORD, and I will bring you out (yesa) from under the burdens of the Egyptians, and I will rid you out of their bondage (deliverance), and I will redeem (purchase back) you with a stretched out arm, and with great judgments (avenger): And I will take you to me for a people, and I will be to you a God: and ye shall know that I am] the LORD your God, which bringeth you out from under the burdens of the Egyptians (deliverance). And I will bring you in unto the land (goel), concerning the which I did swear to give it to Abraham, to Isaac, and to Jacob; and I will give it you for an heritage (kinsman) I am the LORD (Exo 6:6).
This idea of kinsman- redeeming lead to the idea of Messiah- Servant. The prophet Isaiah is given magnificent revelation of this idea. Isaiah tells us about the Messiah in Isaiah (9:6). He then explains about the task of being a servant in order to affect salvation to the world (Isa 49:1-6). In Isa 53, we are given one of the most comprehensive explanation of the work of the Saviour. This kinsman- redeemer bore our grief, was bruised of our iniquities (unrighteousness), chastised for our peace, and was beaten for our healing.
Consider This: By definition, the kinsman- redeemer must be related to the person being redeemed. Are we related to Jesus Christ? The New Testament goes to great lengths to establish the fact that we are just not servants of God, but are children of God (Rom 8:16). Since Jesus is the Son of God and we also are sons of God, we become joint- heir with Jesus (Rom 8:17). By virtue of our adoption (Rom 8:15), Jesus is not only our Saviour, but He is also our brother, our kinsman- redeemer, our closest male blood relative.
Thanks for your patience, Mike,
L_____

Hi L____,
This is all very good. I would only add that Christ was also our “near kin” by being “made of a woman, made under the law… taking not the nature of angels, taking on Him the seed of Abraham… the son of Adam, the son of God.” And all of this “while we were yet sinners.”

Rom 4:25 Who was delivered for [ Greek, dia – through] our offences, and was raised again for [ Greek, dia – through] our justification.
Heb 2:14 Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;
Heb 2:15 And deliver them who through fear of death were all their lifetime subject to bondage.
Heb 2:16 For verily he took not on him the nature of angels; but he took on him the seed of Abraham.
Heb 2:17 Wherefore in all things it behoved him to be [ as our kinsman redeemer] made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
Heb 2:18 For in that he himself hath suffered being tempted, he is able to succour them that are tempted.

Christ’s very “inheritance is in the saints.”

Eph 1:18 The eyes of your understanding being enlightened; that ye may know what is the hope of his calling, and what the riches of the glory of his inheritance in the saints,

Just as ours is in Him.

Eph 1:19 And what [ is] the exceeding greatness of his power to us- ward who believe, according to the working of his mighty power,
Eph 1:20 Which he wrought in Christ, when he raised him from the dead, and set [ him] at his own right hand in the heavenly [ places],
Eph 1:21 Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come:
Eph 1:22 And hath put all things under his feet, and gave him to be the head over all things to the church,
Eph 1:23 Which is his body, [ which church is] the fulness of him that filleth all in all.

Your brother in Christ,
Mike