What is "v'Chanah"?
Rashi: It is based and settled, like "va'Hashivcha Al Kanecha" (Bereishis 40:13).
Radak #1: It is a sapling.
Radak #2: It is like v'Ganah (its garden). Chaf and Gimel are pronounced from the same place (so they are interchangeable).
Radak #3: It is the name of a place.
Radak #4: It is like Machon. The Dagesh in the Nun is in place of the omitted [Vov]. This refers to Yerushalayim or the Beis ha'Mikdash - "Machon Shivtecha Pa'alta Hashem" (Shemos 15:17).
Malbim: It is normal to support a vine on a thick branch; this is called Kanah, based on Machon and Kan. This is a metaphor for Malchus Beis David.
What is the meaning of "Al Ben Imatzta Lach"?
Rashi: Esav was a dear son to his father, who called him Bni. You made Gefen Yakov mightier than the Ben - "v'Es Achicha Ta'avod" (Bereishis 27:40).
Radak: Ben is a branch, like "Ben Pores Yosef" (Bereishis 49:22). You already strengthened [the branch], and now You planted it.
Malbim: When a vine's branches spread high, they support it on a tall building, and it grows above. The building is called Ben, based on Binyan. This is a metaphor for the Beis ha'Mikdash.
