Homeworlds

The feature was disabled due to various ways it could be abused, very much like what you are attempting.

I wouldn't call it abuse.  It's like building a palace in CivIV to designate a specific city as your capital.  It definitely should be do-able...

Don't know a way to change the homeworld.  Best thing is to start with a good one...bonus tiles (mines or libraries) depending on your strategy.  Reserve the PQ26 for stock markets.

That's what I assume he wants, to move the higher pop cap and inherent approval bonus to a larger planet to make more money. Again, this is why you can't do it.

You CAN move where your "capital" is, but the capital bonuses are linked to the civ capital improvement, which does not move when the "capital" of your empire moves (say, by you losing or gifting your homeworld).

I recall that there was a patch where the civ capital would automatically move after you conquored your opponent's homeworld. Because this new civ capital was moved to the new homeworld, you could never get this capital unless you managed to destroy the civ, or get them to surrender to you. I remember complaining about it.

Plus there seemed to be some problems with moving the capital around (for instance, the stats of the planets were not being updated correctly) so the devs disabled it.

let me be more clear.  you cannot change your homeworld.  unless for some inexplicable reason you chose to forfeit or destroy.  As Willy said, the bonus' don't move.