there are lots of things you can get to kill stump but may not be able to grow anything on it for a good while after as it may kill your plant to

You can drill holes in the top and put a stump-killer chemical in the holes. This shouldn't harm any climbing plants as long as they don't come into contact with it.

We had an old cherry tree stump in my front garden and I've put a the top of a bird table on top but filled with water for them to have a bath in (it was made of concret)

As Volunteer says, drill several holes into the stump, depending on how big it is, to make sort of tunnels, not right through - then fill the tunnels you've made with SBK, a brushwood killer, and cover with something - a paving slab, anything like that. Wait a month and then it'll be okay to place a container on top with plants inside. If the stump is hollow and you want to grow something in the hollow, you'll have to wait 3 - 6 months to be on the safe side.