While I can understand your frustration at the present situation, I have to admit that I giggled a bit at reading a disgruntled "my ten-week-old is misbehaving!" (Really? A ten-week-old isn't behaving?

)
Look, we've all been there. Infants have blowouts. Toddlers knock over bookshelves. Puppies chew your new shoes. Bunnies spray urine on the newly-painted wall. It sucks. Sometimes it
really sucks. But we deal with it. They grow up. They always grow up.
We made the choice -- one way or another -- to take on the responsibility for a new life.
In your case, it's really not a big deal... although yeah, it's frustrating as heck. Put the kit in an area that minimizes spray mess for now, then get him neutered. That's usually viable starting around 12-16 weeks. What's a few weeks compared to a lifetime of 10 years?
These early years aren't always the most fun to deal with at the time, but they pass.