Bump minimum dbt-adapters version to 1.9.0

[QMalcolm]

Housekeeping

• I am a maintainer of dbt-core

Short description

In dbt-core we've made a switch from an environment variable for gating microbatch functionality to a project flag (#10799). In dbt-adapters we've done likewise (dbt-labs/dbt-adapters#323). For everything to work properly, we need depend on those changes in dbt-adapters, which will go out in 1.9.0

Acceptance criteria

dbt-core depends on dbt-adapters at a minimum of 1.9.0

Suggested Tests

N/A

Impact to Other Teams

N/A

Will backports be required?

N/A

Context

No response