The 9th card you take has no effect on the board state, just pick the one that will give you the most points. The row is not refreshed after you pick. (I'm sure nobody will ever read these tips anyway, since the strategy tips are almost always blank. I'm mostly putting this here for my own reference since the rules summary on BGA for this game is so incomplete.)

As to actual tips: It goes without saying you should aim to have at least one of every card, because that 10 points can decide the game.

If you want a card, but don't want it's ability, you may still be able to do a move that doesn't change the board state. For example, you can swap a potato for another potato and nothing actually changes.