Please I need your help on some basic questions about iphones and versions updating.

Hello. Thank you and I really appreciate you giving some time to read this. I really need your help and im having a hard time searching on google the answers to my basic questions. The reason why im so helpless is because i only have some basic knowledge on this kind of stuff. I also cant activate the phone either since i dont have the right sim and theres no way for me finding the right carrier with the IMEI online without paying and i dont have any credit card or any way to pay online.

Question.
1. Will your phone update to the latest version of IOS once you restore it through Itunes?
info: mine is an iphone 4 im not sure though if its an 4s. I restore d& updated it through Itunes since iphone was disabled

2. I also need some clarifications . Google told me that IOS 7.1 is the likely last version of the aging iphone 4. i believe this post was around 2014.
Source : https://www.google.com/search?client=firefox-b-ab&biw=1760&bih=890&noj=1&q=latest+version+of+iphone+4&oq=latest+version+of+iphone+4&gs_l=serp.3..0i20k1j0j0i22i30k1l8.2644.2870.0.2981.2.2.0.0.0.0.190.190.0j1.1.0....0...1c.1.64.serp..1.1.188.p1DbEAb9SJA&gfe_rd=cr&ei=t9muV4eQEI6E2QTH3rOICQ
~~ If my first question is true, does that mean my iphone 4 version is at IOS 7.1 or did itunes update my IOS to the latest version today? ( i believe its ios 9 with the decimals)

3. If my iphone 4 was updated to the latest version ( i think its ios 9) may i know what is the latest and exact version of the IOS? is it 9.3.4? im not really sure and im having a hard time looking on this since i dont have any great sources . just google and some old post / forums / discussions....


Im looking forward to hear from you guys. these questions really bug me a lot and its the only thing that is preventing me from knowing whether i can still activate this phone i picked up . Sorry for the bad english