7 speed to 8/9 speed Shimano cassette compatibility

Hi everyone,

I have always been building with screw on freewheels or fixed but I have a bike with a cassette that I have been using.
The cassette is a 7 speed Shimano (28T biggest cog), 135mm rear spacing, 1 x7 setup. Hub is Shimano FH-RM30
I would like a wider range of gears, like 34 or 36T max cog cassette. There are very few 7 speed cassettes available.
Couple of questions:
Can I fit an 8 or 9 speed cassette on this body? Thinking on body/cassette width and UG/HG.
Would I need a spacer behind the cassette?
I guess I can use a 9 speed rear mech, is this correct? It's just that they are not much more expensive and they look nicer than 8 speed ones.

Any help appreciated.
Cheers
Alex

Sheldon brown website have something on this.
Iirc: you can use 8,9,10 hg cassette on 7 by removing one of the cog. But all mech, chain and shifter have to use the same original speed for indexing.
8 speed cassette becomes a 7 speed but you still have to use 8 speed stuff for indexing to work.

Thanks for your input.
I had a look earlier at Sheldon's but found the other way round of 7 speed cassettes on 9 speed bodies compatibility.
I'll have a look around and see what the best functional and financial options are.
Can get a 7 speed cassette like the one in the pic for a tenner and will need a new rear mech to have enough wrap.
Or get a 9 or 10 speed one (removing a cog), new rear mech, chain and shifter.
Casettes and rear mech work about the same.
Slightly more expensive because of the chain and shifter but nicer I guess as I have no indexed setup now.

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The altus series 7/8 speed RD such as the m310 is still easy to find here and cheap as hell (about 7,5 pound cheap) ugly though. It should covers up to 34t.
Most low end shimano stuff are made here or Malaysia, so I think that's the reason we've them so damn cheap.

I agree, it looks very similar to the Acera I am using now.
Think I'm gonna upgrade to 9 speed.
Thanks again.