I would only start to worry about looking like an edgelord/weeb/mall ninja with an actual metal sword. No one on the planet is going to get that idea from a bit of Kendo equipment. People might be confused why it's there, especially if you don't do Kendo, but just explain it to them if they ask. Or don't.
At some point, it's your house. Life has enough arbitrary bullshit to offer without worrying about things like this. Just hang it wherever you want, however you want. Act like you're the only person in the world when you do it.