Is it permissible for someone who entered the mosque a few minutes before the Iqamah (call to commence prayer), and there isn't enough time to perform the Sunnah (recommended) prayer before the Fard (obligatory) prayer in its entirety, to remain standing and supplicate until the prayer is commenced, or should he pray the Sunnah prayer in a shortened form?

If one enters the mosque a short time before the iqama, a time insufficient for the rawatib sunnah prayer or the two rak'ahs for greeting the mosque, it is permissible to wait for the iqama while engaging in supplication or other forms of remembrance. If there is enough time for the rawatib prayer, then it is preferable to perform it if that obligatory prayer has a preceding rawatib sunnah, or to perform a supererogatory prayer between the adhan and the iqama. Both of these suffice for greeting the mosque. The rawatib sunnah prayer is sufficient with reciting only Al-Fatiha, and reciting a surah or verses after Al-Fatiha is recommended but not obligatory. Glorification (tasbih) is achieved with a single utterance of "Subhanallah".