b. Evidence of Registration and Use in Bad Faith. For the purposes of Paragraph 4(a)(iii), the following circumstances, in particular but without limitation, if found by the Panel to be present, shall be evidence of the registration and use of a domain name in bad faith:
(i) circumstances indicating that you have registered or you have acquired the domain name primarily for the purpose of selling, renting, or otherwise transferring the domain name registration to the complainant who is the owner of the trademark or service mark or to a competitor of that complainant, for valuable consideration in excess of your documented out-of-pocket costs directly related to the domain name;
Depends on one's standards of ethical. For me it is not. For ICANN, WIPO etc. it is not either. Illegal? It might lead to civil legal action, but most likely only a UDRP.
It depends on what the purpose is for buying it. If you think you will sell it to them then yes that's called cybersquatting and they probably wont buy it from you anyway because if they really wanted it they could just register it themselves for $9 so we can already establish it's not worth $9 to them.
If you have some intended use that would not directly compete with them then that's a completely different question. But this is namepros and the way you asked it and asking it here implies you would try to sell it to them and I would just suggest dont bother.