Does bond length affect bond angle?

Yes, for fundamental geometric reasons. If you have three atoms bonded in a triangle, and you make one of those bonds longer, you will make the corresponding bond angle larger.That said, it doesn't always matter. If you have two atoms bonded to a third but not bonded to each other (e.g. H2O), changing the bond length wouldn't have much effect on the bond angle, because the geometry has no need to change.In general,...

Yes, for fundamental geometric reasons. If you have three atoms bonded in a triangle, and you make one of those bonds longer, you will make the corresponding bond angle larger.

That said, it doesn't always matter. If you have two atoms bonded to a third but not bonded to each other (e.g. H2O), changing the bond length wouldn't have much effect on the bond angle, because the geometry has no need to change.

In general, bond length is a more stable property than bond angle.

Bond length depends primarily on the two atoms being bonded (and whether it is a single, double, or triple bond), rather than on the structure of the molecule as a whole. This is why bond length is considered a transferable property; you can in effect "transfer" the bond length of say a C-H bond to other molecules with C-H bonds (a C-H bond is typically about 110 picometers, if you're curious). In practice, the transfer is not exact; there are still ways that the bond length can change as a result of the structure of the overall molecule, but as a general rule bond lengths are fairly consistent.

Bond angles, on the other hand, can vary tremendously, and are much more dependent on the structure of the molecule as a whole. There is no such thing as a "typical angle for a C-H bond"; it depends on what molecule that C-H bond is in.

We can often estimate the bond angle based on valence shell electron pair repulsion (VSEPR), which is based on the assumption that valence electrons will repel each other by electrostatic force, and seek an equilibrium that minimizes the repulsion. Of course, the real world is always more complicated, and the true structure of molecules deviates from VSEPR due to the wild world of quantum mechanics.