If you are using the DVD iso we already provide, then the repositories on that ISO are from the release of that version, so yes, they will be out of date. You will be required to run a dnf update to get fully up to date post install.
This requires you to have the repositories locally and to use xorriso to combine everything together.
xorriso can be provided a “dialog” or otherwise a script that tells it what to do.
/usr/bin/xorriso -dialog on < /mnt/compose/9/latest-Rocky-9/work/entries/xorriso-x86_64-dvd.txt
Example xorriso dialog from above (trimmed to shorten the post), this lists every single file that will be added to the ISO:
-indev /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/lorax/images/boot.iso
-outdev Rocky-9.4-x86_64-dvd.iso
-boot_image any replay
-joliet on
-system_id LINUX
-compliance joliet_long_names
-volid Rocky-9-4-x86_64-dvd
-update /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/EFI/BOOT/grub.cfg EFI/BOOT/grub.cfg
-update /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/images/efiboot.img images/efiboot.img
-update /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/isolinux/isolinux.cfg isolinux/isolinux.cfg
-update /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/.discinfo .discinfo
-map /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/.treeinfo .treeinfo
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/0136654a4ede48381dc4bf8306af9c273579aae936ceec7e683c82e7cdde7863-other.sqlite.gz AppStream/repodata/0136654a4ede48381dc4bf8306af9c273579aae936ceec7e683c82e7cdde7863-other.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/04bbb4a0-6f6c-49d2-bf99-8fc7bbcdc587-UPDATEINFO.xml.gz AppStream/repodata/04bbb4a0-6f6c-49d2-bf99-8fc7bbcdc587-UPDATEINFO.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/070d8a5d8aceffddf867605b233bd1bd3ab9e3befcaa80a9242230a176f6bf9a-primary.sqlite.gz AppStream/repodata/070d8a5d8aceffddf867605b233bd1bd3ab9e3befcaa80a9242230a176f6bf9a-primary.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-FILELISTS.xml.gz AppStream/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-FILELISTS.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-GROUPS.xml AppStream/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-GROUPS.xml
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-GROUPS.xml.gz AppStream/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-GROUPS.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-MODULES.yaml.gz AppStream/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-MODULES.yaml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-OTHER.xml.gz AppStream/repodata/17038fe5-4604-4b47-8985-91da1f9126e3-OTHER.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/b0f4add3-84c9-4705-a2b5-f4f0b9ecd91b-PRIMARY.xml.gz AppStream/repodata/b0f4add3-84c9-4705-a2b5-f4f0b9ecd91b-PRIMARY.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/da0f35900dcd9e861ede6ad3fc62984bcd5a1521d866f567f08d186e5f7b5ce4-filelists.sqlite.gz AppStream/repodata/da0f35900dcd9e861ede6ad3fc62984bcd5a1521d866f567f08d186e5f7b5ce4-filelists.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/repomd.xml AppStream/repodata/repomd.xml
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/repodata/repomd.xml.asc AppStream/repodata/repomd.xml.asc
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/09bf773e6ca9f0a28fbf7a51026ee76173cb785fad9b383fa7b023ccde0693cf-filelists.sqlite.gz BaseOS/repodata/09bf773e6ca9f0a28fbf7a51026ee76173cb785fad9b383fa7b023ccde0693cf-filelists.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/4c3c542e-0dd5-49fa-9335-9cc6cd0446c7-PRIMARY.xml.gz BaseOS/repodata/4c3c542e-0dd5-49fa-9335-9cc6cd0446c7-PRIMARY.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/78ccc921d9ff0c45f9a22026bedf63e6f99ab68f788a73d467eeeb874d3e3276-other.sqlite.gz BaseOS/repodata/78ccc921d9ff0c45f9a22026bedf63e6f99ab68f788a73d467eeeb874d3e3276-other.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-FILELISTS.xml.gz BaseOS/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-FILELISTS.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-GROUPS.xml BaseOS/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-GROUPS.xml
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-GROUPS.xml.gz BaseOS/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-GROUPS.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-OTHER.xml.gz BaseOS/repodata/ae3999d9-4410-416e-8f49-dd215a1cbff1-OTHER.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/d9675e6d-d2b8-46d4-977f-de7f2e7fe6f1-UPDATEINFO.xml.gz BaseOS/repodata/d9675e6d-d2b8-46d4-977f-de7f2e7fe6f1-UPDATEINFO.xml.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/e6af173e0af860135bb23adb322845d3d9be23788f70235cab98af4cbc315c36-primary.sqlite.gz BaseOS/repodata/e6af173e0af860135bb23adb322845d3d9be23788f70235cab98af4cbc315c36-primary.sqlite.gz
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/repomd.xml BaseOS/repodata/repomd.xml
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/repodata/repomd.xml.asc BaseOS/repodata/repomd.xml.asc
-map /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/media.repo media.repo
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/Packages/3/389-ds-base-2.4.5-6.el9_4.x86_64.rpm AppStream/Packages/3/389-ds-base-2.4.5-6.el9_4.x86_64.rpm
-map /mnt/compose/9/latest-Rocky-9/compose/AppStream/x86_64/os/Packages/3/389-ds-base-libs-2.4.5-6.el9_4.x86_64.rpm AppStream/Packages/3/389-ds-base-libs-2.4.5-6.el9_4.x86_64.rpm
. . .
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/Packages/b/bash-5.1.8-9.el9.x86_64.rpm BaseOS/Packages/b/bash-5.1.8-9.el9.x86_64.rpm
-map /mnt/compose/9/latest-Rocky-9/compose/BaseOS/x86_64/os/Packages/b/bash-completion-2.11-5.el9.noarch.rpm BaseOS/Packages/b/bash-completion-2.11-5.el9.noarch.rpm
. . .
-end
If you are using one that already exists (such as the one from the DVD), you can simply copy it and modify as you see fit by hand. As a word of caution, one slight misconfiguration will break the installer, so it may take experimentation.
If you are making a brand new one to be placed on a new boot.iso, the best way is using the productmd python module. You can find examples of it being used in empanadas shared and empanadas iso utils. You would take the generated file and add it into the iso using xorriso, just like in the example above.