Hello Seed_Time_Harvest, I will have to respectfully disagree with you about who 1 John 1:9 was/is addressed to. Take note that the elder Apostle John includes ~himself~ in the mix of believers who need to confess their ongoing sins to God (to be forgiven and cleansed of them .. not for the sake of maintaining our salvation, but for the sake of our ongoing/growing relationship with our Father).
As such, I also believe that 1 John 1/2 was written to the saints in the church at ~all~ levels of maturity in the Christian faith (see the words in bold below).
1 John 1
8 If we say that we have no sin, we are deceiving ourselves and the truth is not in us.
9 If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.
10 If we say that we have not sinned, we make Him a liar and His word is not in us.
1 John 2
1 My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an Advocate with the Father, Jesus Christ the righteous;
2 and He Himself is the propitiation for our sins; and not for ours only, but also for those of the whole world.
3 By this we know that we have come to know Him, if we keep His commandments.
4 The one who says, “I have come to know Him,” and does not keep His commandments, is a liar, and the truth is not in him;
5 but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him:
6 the one who says he abides in Him ought himself to walk in the same manner as He walked.
7 Beloved, I am not writing a new commandment to you, but an old commandment which you have had from the beginning; the old commandment is the word which you have heard.
8 On the other hand, I am writing a new commandment to you, which is true in Him and in you, because the darkness is passing away and the true Light is already shining.
9 The one who says he is in the Light and yet hates his brother is in the darkness until now.
10 The one who loves his brother abides in the Light and there is no cause for stumbling in him.
11 But the one who hates his brother is in the darkness and walks in the darkness, and does not know where he is going because the darkness has blinded his eyes.
12 I am writing to you, little children, because your sins have been forgiven you for His name’s sake.
13 I am writing to you, fathers, because you know Him who has been from the beginning. I am writing to you, young men, because you have overcome the evil one. I have written to you, children, because you know the Father.
14 I have written to you, fathers, because you know Him who has been from the beginning. I have written to you, young men, because you are strong, and the word of God abides in you, and you have overcome the evil one.
God bless you!
~Deut
p.s. - what human to human relationship can remain healthy and close if the people involved in the relationship do not ask to be forgiven whenever they hurt/sin against one another (so it is with our relationship with God) Remember, for instance, when King David sinned against God (murder and adultery). He asked God to forgive him and to restore the "joy" of his salvation, not salvation itself .. which as @Gideon300 has already mentioned, is not lost when we sin (as we are given "eternal (not probationary) life" from the moment that we first believe .. e.g. Psalm 51:12; John 5:24).