New kitten peed on our bed

We have a new kitten (rescued, male, neutered) Charlie. His 9 1/2 weeks old. We have had him less than a week.

He has been using the litter box without any issue or accident.

Today was the first day he was alone for more than a few hours. I just noticed he peed on our bed.

Was he scared, upset/mad or something else? Any advice??

Thanks in advance

At 9 1/2 weeks he is very young; the equivalent of a young human toddler.  He is likely to have accidents here and there; especially while he is alone if he has free roam.  I would suggest keeping him in a smaller space when you cannot supervise him.  

My 2 stayed in a large wire dog crate at night and when we were at work when they were kittens.  It had a small litter box in the back, a bed and toys in the middle and food and water in the front.  This helped them with the bathroom accidents, kept them out of my fish tank and other kitten safety hazards, and it also helped us train them to let us sleep at night.  I do think it helped they were together in there.  At our old house there was a larger than average gap underneath the doors.  The first night my 2 were home they got out of the spare bathroom we'd set them up in by crawling under the doors!  We woke up in the morning to find them in the living room watching our fish tank!  They were 10 weeks old.  

I recently found this picture of them; 9 years ago!

Thank you!

I was trying to contain him in the master bedroom/bathroom. I set up his box and some food/water in the bathroom and toys etc in the bedroom. Saturday he will be alone for my 12 hour work shift. Yesterday was just a 4 hour stint alone while I ran errands. I hope he isn't too scared. It breaks my heart.. the poor little guy.

I will see how it goes and if he keeps having accidents I will try a crate. His current crate is so small I don't want to confine him in that space for too long.

and your kittens are adorable! Charlie is about that little now. They grow too quick!

You might consider adding a few extra litter boxes; so he doesn't have so far to go when he realizes he needs to.  If you have a safe master bathroom; that might be better while you are at work.  You can make it cozy for them.  Some even love a "mama' size stuffed animal to curl up with.