Can I use methanol acidified with HCL as solvent to elute high polar compounds during fractionation using glass column ? And why it's preferable to use acetic acid than HCl
You may use HCl. Acetic acid is generally preferred because salts of acetic acid (or formic acid) are generally volatile. Hydrochloric acid might react with some metal parts if using a chromatography system. Depending on the silica grade, HCl might wash some metal ions from the silica (sodium, potassium are common in less expensive silica).
It is good to use HCl of concentration below of 0.1 M for which pH will be greater than 1, above 0.1 M concentrations it may react with silica or other adsorbents. Not necessary to use a volatile buffer every time.