24" is a wheel size, not really a bike size. Not all 24" bikes are the same size, and not all 9-year olds are the same size.
Basic rule of bike fitting is that there should be 2" or more of clearance between the crotch of the rider and the top tube when straddling the bike. Then the saddle should be at such a height that the rider's leg is almost fully extended with the foot on the pedal in it's lowest position.
Any bike that allows for this has a chance of being a decent fit.
When deciding what bicycle to buy, consider factors such as your budget, the type of riding you plan to do (road, mountain, commuting), the bike's size and fit for your body, the quality of components, and any additional features or accessories you may need.
The best time of year to buy a bicycle is typically during the fall or winter months when bike shops offer discounts to make room for new models.
I would buy the next size up from his pants size. If he wears a 12 I would get a 14
buy one from a shop huggies size 6 should fit if he/she is skinny
Shopping for discounted winter clothes, buy electric or ordinary bicycle, buy and install some solar applications to my house.
small size
You should buy one that meets your requirements and budget.
For a 14 year old boyfriend, you can buy him a mountain bicycle, to mark your one year anniversary.
Check the sticker on the drivers door jamb, it will list the size it was built with. That is the size you should buy.
9
You can buy a street bicycle at a local bike shop, sporting goods store, or online retailer.
It depends on size and gender. For example buy a male pitbull ,and since it depends on size,it should cost around six hundred.