Is Ruby a useful language going forward for programming for tablets?

Is Ruby a useful language going forward for programming for tablets?

I hope this(these) question isn't too vague. I've been on and off again
programming since highschool. I learned Pascal there, then C++, and
finally some Java in college. Then didn't spend much more time
programming. Obviously a lot has changed in the past 13 years, and besides
Minecraft, it doesn't appear Java ended up being quite as important as
they told us it would be back then. But I'm curious to start programming
again and a lot of (slightly older articles) were touting Ruby. I was
looking into Ruby but I'm a little confused by it. I read the wikipedia
page and looked through some sites.
Being somewhat familiar with Java, Java gets compiled to bytecode and run
on the JVM. Since all JVMs have to support the standard, if you made a,
say, graphical-windowed program with Java/Swing, any JVM on a computer
with windowed environment would run it.
Of course, neither Apple nor Android tablets support Java or have a
JVM(although android is Java-like)
Is this sort of how Ruby works too? Is there a ruby "JVM"? I saw something
about the MRI but this is only one specific ruby interpreter, correct? And
there isn't a ruby interpreter on tablets, is that also correct? And there
are many different ruby GUI toolkits like FXRuby, but would these work on
multiple devices including tablets? When installing your program, do you
need to include distributables to install along with your software so your
program can run? And moreover I saw something like RubyMotion for
developing for iOS, does this basically "recompile" your ruby program to
objective-C so it will run on an iOS device? You obviously can't install a
ruby interpreter on an iOS device without violating Apple's ToS...
I'd also like to start teaching my kids to program a little since it's so
incredibly useful. I'm starting with Scratch but will Ruby be useful for
tablet and portable device programming in the future? Or is it fairly
limited to devices with a fuller featured operating system?
Sorry to pepper with so many questions. I hope this is an okay forum for
that.