Theres a bend in my rear derailleur. All the rear gears are working nicely. Although when I want to change into the highest (9sp) the chain doesnt seem to be catching the chain ring to go into gear. This I think is because of the bend….anyway it can be bent back?

You can try and bend it back but it’ll be a nightmare to get it perfect again

could try to, but then this could put stress on the bend and snap something. just undo the screw on the mech half a turn for the chain then to sit on the 9th gear

There are gear hanger alignment tools
http://www.weldtite.co.uk/607/pages/tools-podcasts/how-to-use-cyclo-tools-gear-hanger-alignment-tool.aspx

but it can be possible to straighten it with out the tool.
http://www.cyclus-tools.eu/rahmen.html?&L=3