I would think 5 months would work. The plants would have to pretty much be in a dialed in garden to push a pound per plant in 5 months. Not saying it couldn't be done.. but would be a challenge I would love to undertake if I had a forklift for my plants.. j/k
In a 5 month schedule, I would think they would be planted in the beginning of May inside, put outside in it's permanent planter the beginning of June then force flowered from mid-July through beginning of October. 9 months would most likely be 2 or 3 months of prepping the garden out.