Two official numbers sit side by side. The game description says play solo or with up to 8 players. The Roblox experience record sets max players to 20. A full server can therefore hold more people than the group the description is talking about. Invite friends with Roblox's normal party tools so you land together. There is no published in-game voice channel and no published player-versus-player mode.
What a group changes, and what it does not
Taming is still three bones and a right click. The map is still M. Shelter is still something you place. The 10 endings are still unnamed. The Last Gift is the badge that talks about other people: everyone went down, and Jerry brought you home. A solo player should not expect that sentence to describe their run. Other badge texts do not say they require a group. Bad Owner, Put Down, Morning, and The Stray read as things that can happen to one player and one wolf.
Split the first day only if you can still meet before dark. One person on wood, one on stone, one holding bones is the useful split. Scattering into the cave on the tunnel screenshot, with half a hunger bar, is how a group wastes the night. Agree when to sleep. Sweet Dreams is your own bed, so each player needs a bed if each player wants that badge.
What stays dangerous with friends
The night media still shows a tall black figure in the trees. The listing still warns of jumpscares and blood. Extra players do not remove Jerry. In Survival he is out hunting for Night Shift whether or not you brought friends. Creative Mode's "Jerry leaves you alone" applies to the pass owner in Survival, not to the whole server by default. The pass text does not say it pacifies Jerry for everyone else.