He could grow a variety of 'em and do some other stuff thanks to his unique 9-stars blessings
("Sevenstar"/7 stars from God of Agriculture Kronos; 1 hero's star from God of Heroes Herkebaric/t; and 1 star from God of Blacksmithing Vulcan)
I feel, even if he did marry all of them....he would still come up with an excuse to put physical distance between him and them or come up with reasons not to embrace them.
If the girls don't push him into it or he gets an "after-effect" like in Isekai Nonbori, he's not going to really do much as their Husband King.