Yes, you can legally buy and use Delta-9 products derived from hemp as long as the dry weight of the Delta-9 in the edible or flower is .3% or less.
Way before the 2018 federal Farm Bill was passed that relaxed the laws regarding the production, possession, use and sale of hemp, Montana beat them to the punch. Senate Bill 261 passed the Montana legislature in 2001, legalizing the cultivation and production of industrial hemp.
Cannabis laws loosening
Many of the western states, the East coast and pockets of the South and Midwest have loosened their cannabis laws, including legalizing marijuana in controlled amounts for adults over 21 years of age and those prescribed the drug to treat a medical condition.
While unlikely, because of the drug’s illegal status at the federal level, arrest remains a possibility if you possess or use marijuana. As the law stands today, however, the use of Delta-9 in the above concentrations is legal at both the state and federal levels.
If you encounter police with Delta-9 in your possession
Maybe you’re snowshoeing across federal lands with a friend and decide to smoke some Delta-9 flower. A ranger with an ax to grind could claim your legal Delta-9 was indistinguishable from federally illegal marijuana. You could face arrest.
Even in situations where you know you are in the right, it doesn’t pay to try to hold court in the street. Don’t argue with the law enforcement officer. Comply with the process and ask to speak to a criminal defense attorney. Then, state your wish to exercise your Constitutional right to remain silent.