Indiviual words and short phrases such as titles cannot be protected by copyright. However, they can be protected by trademark law. "Android" is a trademark in the US, in the EU, and I am pretty sure in most if not all other countries.
Trademark protection is specific to a purpose or area. If you are writing an SF novel which contains an artificial being, you can describe that being as "an android" without infringing the trademark protection on the mobile phone OS. However, using the term "android" to describe a pieces of mobile phone software is likely to be an infringement.
Trademark law is different in different countries. For example, in some countries, there is no protection unless a trademark is registered. In others, including the US, simply using a term to label a product or service in commerce can create protection, although registration can give additional rights to the trademark holder. The exact rights protected and the standards for measuring infringement will also vary, but there are many similarities in trademark laws across the world.
One can use a trademark to refer to the trademarked product or service, and this is not an infringement. For example, one can write a review of Android phones vs Iphones, and use the term "Android". This is called "Nominative use" or sometimes "Nominative fair use". One must be careful not to imply that the trademark owner has approved, endorsed, or sponsored the use. With a review, this is usually fairly obvious. But in other cases of nominative use it can be more of an issue. For example, one might write in an advertisement "This software is compatible with Android phones." That is nominative use, but a reader might think that the software has been in some way approved by the trademark holder. The ad should therefore make it very clear that there has been no such approval, sponsorship, or affiliation. This is often do0ne with an explicit disclaimer, such as "XYZ software is not produced by, approved, sponsored by, or affiliated with Android, which is a trademark of Google."
In general one should use no more of a trademark than is needed to identify a product under nominative use. It is generally better practice to sue the name, but not the logo. Use of a logo is more likely to appear to indicate some sort of affiliation. But this is not an absolute rule. For example, a product which is compatible with many other products might display a list of logos, provided it makes clear that this merely indicates compatibility. not approval.
The basic standard is that one may not use a trademark so that a reasonable person, a customer or potential customer, might plausibly be confused into thinking that a product or service comes from the trademark holder, or is in some way approved by, endorsed by, or is affiliated with the trademark holder, or that the reputation associated with the trademark properly attaches to the product that uses the trademark without permission. Also, one may not use a trademark so as to dilute it, treating it as a generic term for all products of a similar type. For example, one should not use "Xerox" as a synonym for "photocopy", as that dilutes the Xerox trademark.
One may offer training or instruction about a trademarked product, and one may use the trademark to identify the product about which instruction is begin offered. This is a form of nominative use, and like other forms, the user must make the lack of any affiliation clear, and avoid possible consumer confusion. This would apply to publicly posted videos.
Using a handle such as "AndroidGuy" to indicate that one is a fan of, or an expert with, Android phones could be a form of nominative use, but seems rather likely to create confusion. If others might reasonably think this indicates that "AndroidGuy" is some sort of official representative of Android, or has in some way been approved or authorized by Google, that would be infringement.
A channel name, unlike a handle, comes with a description, that could help clarify the lack of affiliation. But again, if anyone might reasonably be confused into thinking the channel or the videos posted there are sponsored by Google, that might be infringement. If the videos are being sold, or are used to advertise commercial courses or any other products or services, one must be particularly careful to avoid any implied affiliation.
Trademark infringement, like copyright infringement, is usually a civil matter, not a criminal one. That means that the trademark holder must bring a court case or other legal proceeding to stop the infringement, or to recover damages or penalties. Some holders are more aggressive about this than others. This also means that a holder can file suit even in cases that are clearly permitted nominative use, and it is up to the defendant to assert and demonstrate that the use is permitted under the relevant law. Google can hire more lawyers than an independent developer can.
