Matthew Poole and continuators on Psalms 80:9

9 Thou preparedst room before it, and didst cause it to take deep root , and it filled the land.

Or, didst purge or cleanse the Soil, taking out stones or sticks, or other roots or plants which might hinder its growth or fruitfulness. Thou didst root out those idolatrous and wicked Nations which might either corrupt or destroy them.

Thou gavest them a firm settlement in that Land.