a true bonsai is root pruned. I had one in a pot for years which kept it very small. I moved it into a bigger pot and it got bigger.

so if you want to keep it small keep it in a small pot.

No reason why not. I would possibly do it over 2 years.....this year remove 1/3 of the roots and pot it into a slightly smaller pot...keep well watered and fed.

You might want to look at training it into the style of your choice with wires....don't leave them on for too long or they will scar the branches...6 months max.

The following year, remove another 1/3 of the roots, especially any tap roots. Try to encourage a nice fiberous root system. Pot into a Bonsai dish of your choice using a decent, well drained compost or akadama.

Continue to train to your chosen style by pruning and wiring.

Good luck, miss my Bonsai :-(