Jamieson, Fausset and Brown on Hebrews 9:8

8. The Holy Ghost--Moses himself did not comprehend the typical meaning (1Pe 1:11, 12).

signifying--by the typical exclusion of all from the holiest, save the high priest once a year.

the holiest of all--heaven, the antitype.

the first tabernacle--the anterior tabernacle, representative of the whole Levitical system. While it (the first tabernacle, and that which represents the Levitical system) as yet "has a standing" (so the Greek, that is, "has continuance": "lasts"), the way to heaven (the antitypical "holiest place") is not yet made manifest (compare He 10:19, 20). The Old Testament economy is represented by the holy place, the New Testament economy by the Holy of Holies. Redemption, by Christ, has opened the Holy of Holies (access to heaven by faith now, He 4:16; 7:19, 25; 10:19, 22; by sight hereafter, Is 33:24; Re 11:19; 21:2, 3) to all mankind. The Greek for "not yet" (me po) refers to the mind of the Spirit: the Spirit intimating that men should not think the way was yet opened [Tittmann]. The Greek negative, "ou po," would deny the fact objectively; "me po" denies the thing subjectively.