I do not believe we need to confess in order to receive forgiveness. Forgiveness is granted through the mercy and grace of Father.
If forgiveness was based upon our "confessing", what would happen if we forgot to confess one area of our stumbling (missing the mark)? Is forgiveness then lost to us? I do not believe that was the point of 1 John 1:9.
I believe that our "confessing" is more for our peace of mind than for forgiveness. God has already told us He forgives all our iniquities and has removed our sin as far as the east is from the west, that He knows our frame and remembers we are dust (Psalm 103).
Proverbs 28:13 tells us He that covereth his sins shall not prosper: but whoso confesseth and forsaketh them shall have mercy.
The reason we conceal anything from Father is because we do not trust Him. We are afraid of Him so we try to hide what we have done from Him.
We need to get to the point where we have no fear of Father and we trust that when we go to Him in whatever state we find ourselves, He will always take us in, hold us close, and reveal to us His never-ending, all-abounding love.
When we hide from God, we are following the way of Adam.
Job 31:33 If I covered my transgressions as Adam, by hiding mine iniquity in my bosom
When we hide from God, it is not healthy for us:
Psalm 32:
2 Blessed is the man unto whom the LORD imputeth not iniquity, and in whose spirit there is no guile.
3 When I kept silence, my bones waxed old through my roaring all the day long.
4 For day and night thy hand was heavy upon me: my moisture is turned into the drought of summer. Selah.
And when we [finally] turn to Father and reveal our hearts to Him:
Psalm 32:5 I acknowledged my sin unto thee, and mine iniquity have I not hid. I said, I will confess my transgressions unto the LORD; and thou forgavest the iniquity of my sin. Selah.
I realize these are OT Scriptures, written prior to Pentecost and the outpouring of HS, but we also read that whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the Scriptures might have hope (Rom 15:4).
We can learn from these great men and women of God who went before us in faith and wrote those things that helped them in their time of distress, sorrow, anger at themselves because they stumbled.
Does our not confessing mean that we are no longer sons of the Most High God? No!
However, when we go to Father and have our heart-to-heart with Him, it clears our minds and frees us up.