An 8 year old would have to have come with someone (family member, relative, neighbor) and be headed to a particular person. He would not have been permitted to board the ship alone and would not have been admitted to the US without someone responsible for him. He should appear in at least the 1910 census and any censuses thereafter, and probably have a WWI draft card. Without a name it is difficult to help look for information for you.
If you know the village or area that he came from and his surname in that area, you can search the Yad Vesham Archives https://www.yadvashem.org/archive.html looking for his relatives that either perished or survived the Holocaust.
Dear Ms. Carrasco,
Thank you for posting your request on History Hub!
In addition to the information from the previous poster, we suggest that you request a copy of his Official Military Personnel File (OMPF). OMPFs and individual medical reports for enlisted men of the U.S. Military who were separated from the service after October 1912 and prior to 1958 are in the custody of NARA's National Personnel Records Center in St. Louis. In many cases where personnel records were destroyed in the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Please complete a GSA Standard Form 180 and mail it to NARA's National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. For more information see Official Military Personnel Files (OMPF), Archival Records Requests.
Due to the COVID-19 pandemic, the NPRC was closed from March 23 through June 23, 2020. As of June 24, the NPRC entered into Phase One of a gradual reopening process. The center is currently only servicing emergency requests associated with medical treatments, burials, homeless veterans, VA Home loan guarantees, and employment opportunities. If this is urgent, please see Emergency Requests and Deadlines. We apologize for any inconvenience.
Most cities and counties have yearly directories for residents. Some of these directories are indexed by address but most are alphabetically by last name. We suggest you consult the FamilySearch wiki on United States Directories to search for this ancestor during the timeframe in which he resided in Chicago.
We hope this is helpful. Best of luck with your family research!