If I buy a bottle of wine or other alcoholic beverage while visiting another state, will I owe the 9% tax when I bring that bottle into Maryland?

That depends. If you pay a sales tax to the vendor in the state where you made the purchase and the rate of that tax is equal to or greater than the 9% rate, then you will not owe any additional tax when you bring the item into Maryland. However, if you are not charged a sales tax on your purchase, or if the amount of tax you pay is less than 9%, you will owe Maryland tax on the difference between the rate you paid to the other state and the 9% Maryland rate. You should also be aware that if you bring alcohol in excess of the quantity limitations specified in Tax-General Article §5-104(c) you will also owe the alcoholic beverage tax in addition to the sales and use tax.