Is it permissible for an Islamic scout association to use scout musical instruments (such as the tambour, drum, clarinet, trumpet, saxophone, and song) to play military marches at receptions and events, to bring joy and happiness to its activities, given that other scout troops use musical bands?

Using and listening to musical instruments is forbidden, with the exception of the duff (tambourine) for women during the two Eids and at weddings, according to the soundest opinion. This is based on the Prophet's (peace be upon him) saying: "There will be among my Ummah people who will consider unlawful sexual intercourse, silk, wine, and musical instruments to be lawful." A group of scholars has related a consensus on the prohibition of listening to musical instruments. All the instruments mentioned in the question fall under the meaning of musical instruments (ma'āzif).