That is not what Hebrews 4:9 is speaking of. Please follow along.
So there remains a Sabbath rest for the people of God. For he that is entered into his rest, he also hath ceased from his own works, as God did from his.
(Heb 4:9,10 )
When and where did God cease from His own works? Well it just so happens that the writer of Hebrews tell us.
For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works. And in this place again, If they shall enter into my rest.
(Heb 4:4-5 KJV)
W. E. Vine, Greek Dictionary: SABBATISMOS (4520), a Sabbath-keeping, is used in Heb. 4:9, R.V.,
"a Sabbath rest," A.V. marg., "a keeping of a Sabbath" (akin to sabbatizoµ, to keep the Sabbath, used, e.g., in Ex. 16:30, not in the N.T.);
here the Sabbath-keeping is the perpetual Sabbath rest to be enjoyed uninterruptedly by believers in their fellowship with the Father and the Son, in contrast to the weekly Sabbath under the Law. Because this Sabbath rest is the rest of God Himself, its full fruition is yet future, though believers now enter into it.
Hebrews 4:10 says the one who has entered His rest has himself also rested from his works, as God did from His. That person has entered in God’s rest through Jesus "rests from his own work" (in contrast to Law keeping) as God ceased or rested from His works in the seventh day of Creation. God's ultimate, true rest did not come through Joshua or Moses, but through Jesus Christ. Joshua led Israel into the promised land, which was merely the earthly rest which was but a shadow of what was involved in the heavenly rest. The rest in Christ that God offers is spiritual and is superior. Israel's earthly rest was filled with conflict and attacks from their enemies and the daily cycle of work. The "sabbatismos" rest enjoyed uninterruptedly by believers in their fellowship with the Father and the Son, in contrast to the weekly Sabbath under the Law, is found only in Christ and not Law keeping.
Although for centuries the Jews had found their physical rest in a day, the New Covenant takes the focus off the shadows of the Old Testament signs and rituals and reveals their spiritual substance --
the fulfillment/reality—in the person of Jesus Christ. (Colossians 2:16-17) Christians find complete Sabbath "sabbatismos" rest in Christ's finished work on the cross. The New Testament Sabbath rest is entered into by ceasing from one’s "works" of trying to earn salvation though keeping the Law. Paul explains that the Jewish holy days, including the weekly Sabbath, were merely a “shadow” which pointed to Christ; therefore, Christians should not feel obligated to observe them once the “reality” has come (Colossians 2.16-17). Because Jesus and the New Testament writers never reiterate the Sabbath command as they do the moral principles contained in the other 9 commandments, Christians are not obligated to observe a literal weekly Sabbath day.