The Check merge-up step fails the 2.9 release dry run because the merge-up PRs #2692 and #2696 were squash-merged, so 320b0012 (GODRIVER-4210) and dcf39794 (GODRIVER-4222) are on master by content but not by ancestry, and git log origin/master..HEAD still lists them.

Merge release/2.9 into master with git merge --strategy=ours origin/release/2.9 (master's tree is unchanged) and land the PR with "Create a merge commit", not squash. Before pushing, confirm git log origin/master..origin/release/2.9 lists only those two commits. Then re-run the release dry run.